Most watch brands build watches that fall into two categories: the dress watch, for when you need to get out that suit you've not worn in two years because cousin Eddie is getting married, and the more casual tool watch, because cousin Eddie is getting married on a baseball field.

Beyond being not dressy, tool watches do jobs: divers tell you how long you have before you get the bends, chronographs tell you how fast you're going, field watches allow you to coordinate the invasion of Normandy, and so on. We say most brands because Rolex doesn't make tool watches. They make 'professional' watches, implying that every Daytona wearer drives for McLaren. (They don't. At best, it's Sauber.)

But then there are professional watches built specifically for actual professions, bringing us to this issue of The Five. From counting your pulse to setting your shutter speed, here are five tool watches with actual jobs to do.

If you're from a place that sees thunderstorms, you're certainly aware of this part-folklore, part-physics experiment: when you see lightning, start counting. When you hear thunder, the time elapsed tells you how far the storm is from your location. If the count is less than 30 seconds, you're in the danger zone, Kenny Loggins.

The physics is real: sound travels at 343 metres per second, more or less. Light, on the other hand, covers roughly 186,000 miles in the same period. It’s like a lot faster. Anyway, in counting the time difference between a lightning strike and a thunder clap, you are actually measuring something real, the accuracy of which depends on whether your saying "One-Mississippi" takes an actual second.

Fortunately, Nezumi Studios is here to take the guesswork out of the enterprise. The Tonnerre ('thunder' in French) has a telemetric scale on its chapter ring, designed to help you measure the distance between an event you can see (a lightning bolt, in this case) and when you hear the event (thunder). You see telemeters from time to time, from brands like Citizen to Longines.

Stockholm-based Nezumi has earned its share of watch crowd love by making vintage-style watches for the racing set, chronos of course, but tool watches too. They collab'd with NY thrash legends Anthrax, which means you can now calculate how far the band is from your row by measuring the time elapsed between seeing the headbanging and hearing "Caught in a Mosh."

Does it do a real job? Yep, if you need a telemeter. Soldiers, storm chasers, professional firework launchers — all could do with one.

38mm stainless steel case, Seiko V63 meca-quartz movement, 50m water resistance

The measurement of your vital signs: heart rate, respiration rate, blood pressure and temperature, goes back a ways. It was Hippocrates himself who taught doctors to measure temperature by touch (something your mother did when you were trying to fake a fever to get out of going to school). Most vital signs have deep historic roots, though blood pressure is the exception: a 19th-century invention, credited to two men with brilliantly 19th-century names. Samuel Siegfried Karl von Basch invented the sphygmomanometer (the thing that measures your blood pressure), while Scipione Riva-Rocci gave us the inflatable cuff that, more or less, is still used today.

With all this measuring, there had to be a role for watches. It was 18th-century English physician John Floyer who first believed heart rate needed accurate measurement, enlisting London clockmaker Samuel Watson to build a tool for the job…and the pulsometer was born. Later, scales were added to measure respiration, too, giving us the not-quite-as-popular asthometer scale as well.

For a time, the pulsometer watch was de rigueur in hospitals: Rolex, Longines, Gruen, Eterna and Omega all made them. Digital tools eventually made them redundant, though they can still pull an emergency shift (pun intended) in, say, the backcountry.

Our watch is the Medic II by Singapore-based Boldr, a brand well regarded by the trades for its tough, field-worthy watches. The Medic II has two scales: a pulsometer graduated to 30 beats, and an asthometer graduated to 5 breaths. Those are, by the way, the only instructions you need: start the timer, count 30 beats or five breaths, and the watch tells you what you need to know.

Does it do a real job? Sure, though this is probably a tool watch for the field, rather than an operating theatre.

38mm titanium case, Seiko V64 meca-quartz movement, 200m water resistance

If you’re a decision maker at your company, you need to be on the bleeding edge of, well, everything. But before you go signing up for seminars, conferences, lunch ‘n learns, and all that jazz, just know there’s a far better (and simpler) way: Subscribing to The Deep View.

This daily newsletter condenses everything you need to know about the latest and greatest AI developments into a 5-minute read. Squeeze it into your morning coffee break and before you know it, you’ll be an expert too.

Subscribe right here. It’s totally free, wildly informative, and trusted by 600,000+ readers at Google, Meta, Microsoft, and beyond.

Let's chat beer, shall we? In 1984, nuclear physicist and beer enthusiast Charlie Papazian published The Complete Joy of Home Brewing. Charlie found an immediate audience. At the time, American beer was dominated by a few big brands, all more or less producing the same thing: pale American pilsner, each entirely uncontaminated by flavour. Papazian’s book started a revolution, first in the kitchens of thousands of Americans, some of whom went on to launch the craft brewing industry we see today.

Reading the book, one learns that beer-making is as much science as art. And there are a lot of things to measure: gravity (the amount of sugar in your beer), pH, attenuation (how much sugar the yeast converts to alcohol, more or less), IBUs (international bitterness units), a variety of temperatures, and of course time: boil time, fermentation time, and a few others.

Which brings us to Brauer. Founded by a watch and homebrew enthusiast, the team includes PhDs in computer science, marketing, chemistry and maths, plus one genuine watchmaker. The result is a company built for one purpose: making watches for home brewers. We'll let Brauer describe what the Brewday actually does, because frankly, they say it better than we could:

"The rotating bezel is specially designed to count the standard wort boiling times from 90 to 60 minutes. It also shows the exact time of all hop additions during the boil as specified in the recipes... (the watch) can be used by homebrewers to convert gravity between Plato, SG points and Brix, weight, volume and pressure between imperial and metric units and vice versa..."

If that all makes sense to you, this is your grail. Full of your finest homemade ale.

Does it do a real job? Given that 94% of homebrewers wish that brewing were their real job (a number we completely made up)…absolutely.

41mm stainless steel case, Seiko V67 meca-quartz movement, 100m beer water resistance

Watches and cameras have a lot in common. Both have had their moments of severe disruption (the quartz crisis, the digital revolution). Both have been more or less replaced by the phone in your pocket. And Leica, bless them, makes an excellent if not totally overpriced version of all three. (Leica fans, our email for complaints is in the footer.)

For a camera, it's all about light: how long the shutter stays open, the size of the hole (not a technical term) through which light travels, and ISO. ISO was originally a measurement of film sensitivity: the higher the number, the more sensitive the film was to light. When digital cameras arrived, they kept the same scale, partly for simplicity, partly because photographers already understood it. Your grandfather's Kodachrome? It had an ISO rating too. Get the three — shutter speed, aperture and ISO — in balance and you have a great photograph. (Or more accurately, a well-exposed photograph. You still need to focus.)

One almost universally accepted photography hack is the Sunny 16 Rule. On a bright sunny day, set your aperture to f/16 and your shutter speed to match your ISO. Shooting ISO 100 film? Set your shutter to 1/100th of a second. The rule gave photographers, pros even, an incredibly effective reference point when working without a light meter.

The Obscura II builds the Sunny 16 Rule directly into the watch. Rotate the bezel to align your aperture with your ISO, and the watch gives you your shutter speed. Sunny day or overcast, ISO 100 or 400, it's all there on your wrist. Nodus, an LA-based microbrand with a serious following among watch enthusiasts, developed the Obscura II in collaboration with Beers and Cameras, an analogue photography community, and patented the exposure gauge complication in 2024. It's the first watch ever to do this.

One more detail worth noting: the bronze crown and bezel grip are finished in black DLC coating, which wears away over time, revealing the bronze underneath. A watch that ages like a classic camera. Leica or otherwise.

Does it do a real job? Oh yes, it very much does for photographers. And it looks great doing it.

38mm stainless steel case, TMI NH38 movement, 100m water resistance

We're risking cliché here, featuring a watch for those with the 'spy job.' After all, James Bond elevated Omegas, Rolexes, Seikos and a few other brands to EDC weaponry. But for this issue, we're interested in a watch for actual spycraft.

Now, you may be saying, "What? That Rolex Submariner that Roger Moore used to unzip Miss Caruso's dress? That is not spycraft?" No, it isn't. That's the Roger Moore version of James Bond jumping the shark. Our watch for spies is the Bernhardt Cipher, and it's a nod to the amazing world of cryptography. Cryptography is the science of code, or more specifically, code that only you and those you choose can understand. In cryptography, a cipher takes a message and scrambles it into something unreadable to anyone without the key.

One of history's great cryptographers was Thomas Jefferson, third President, author of the Declaration of Independence, and, as you may know from 8th grade history, a serious inventor. Jefferson designed the wheel cypher, a mechanical device consisting of 26 rotating discs, each inscribed with the alphabet in a different order. To encode a message, you'd align the letters of your text across the discs, then read off any other row as your cipher. To decode it, you'd reverse the process. The US military used a version of Jefferson's wheel cypher well into the 20th century.

Which brings us to the Bernhardt Cipher Diver, a watch developed in partnership with Jefferson's Monticello and released to coincide with the United States entering its 250th year of independence. North Carolina-based Bernhardt is an O.G. among American microbrands. Founded in 2005 by the late Fred Amos, his sons continue his work of creating unique, field-ready watches with high specs and something of a cult following. Bernhardt does customs, too. For example, if you want a special watch for the boys in Precinct Nine, or just one if you want a custom watch yourself.

The Bernhardt Cipher is also a real cipher: alphabetic characters are printed beneath the sapphire bezel in UV-reactive ink. During normal wear, they're completely invisible. Illuminate the watch with ultraviolet light and the cipher is revealed, usable alongside the watch's fixed time references and dive bezel to encode and decode messages. The case is rated to 300 metres and the cipher mechanism is patent-pending.

A working spy watch. Jefferson would approve.

Does it do a real job? As a cipher that looks great, yes. Does it explode, cut through moving trains, teletype or have a TV? No. But let's keep it real.

41mm stainless steel case, Miyota 9039 automatic movement, 300m water resistance

Watch500 publishes two newsletters: News from the GMT, covering watch news and industry insights, while The Five brings you themed watch picks.

Get the best watches that don’t require a second mortgage or the sale of a vital organ - new releases, brand discoveries, industry insights, and the stories behind timepieces that are eminently affordable, framed around culture, history, art and whatever rabbit hole we fell into during the week.

And feel free to pass this along to someone else who doesn’t need another watch, but will probably buy one anyway.

Prices are approximate, converted to GBP or USD when needed, and they may wander a little depending on tariffs, exchange rate mischief, or the usual forces beyond our understanding or control.