Watches Rated to 300 Metres. Deepest Dive: The Bath

That ladder up there is for divers. Now for the number on the watch you actually own, because it's far less literal than it looks.

Take the humble "30 metres". It doesn't mean your watch can go 30 metres down. It means the watch passed a lab test, sitting perfectly still under pressure. You don't sit still. You swim, splash and wave your arms about at a barbecue. So, brands translate the number into everyday life, and the translation is stricter than you'd guess:

• 30 metres: rain and a quick hand wash. Not swimming. Not showering.
• 50 metres: a slightly braver watch, but still no hot showers or saunas.

Most watches carry a rating in that territory, which is why so many owners get a soggy surprise.

A 100-metre rating on an everyday watch handles swimming. That isn't the same as a 100-metre diver's watch, which has to meet a tougher standard: a dial you can read in the dark and a way to time your dive, on top of the pressure test.

Brands differ, so the useful question isn't "how deep can I go?" It's "what does the maker approve this watch for?" Ask before you dive in.

Two habits help every watch. Screw the crown down if yours has that feature. And remember that seals age, so some retailers suggest a water-resistance check every year or two. Think of it as a small service for a loyal friend.

So, when a mate says, "It's water resistant to 30 metres, so I'll swim in it," stop them gently. They own a lovely watch and a slightly optimistic imagination

We say this with love:

• The rotating bezel exists so a diver can track how long they've been underwater. Yours has timed the toast. And, if you own one of our award-winning Manta or Manta Revelare dive & sports watches, then we know, for sure, you’ll have got almost illegal amounts of pleasure from the 60-crunchy clicks from our bidirectional inner rotating (compressor style) bezel.
• The glowing dial has to stay readable in total darkness. Yours has found the loo at 3am.
• The running seconds hand lets a diver check, at a glance, that the watch is still alive. Yours checks whether the meeting is.

Because we don't buy the dive. We buy the margin.

Nobody buys a 4x4 for the mud. Nobody buys a rain jacket for the Himalayas.

We buy them for a feeling: if it all kicks off, we'll be fine. Your wrist believes you might be in the Maldives by teatime. But you’re in your local hardware store. Both of you are happy.

That's not vanity. That's optimism, machined in steel.

There's something practical hiding in the joke, too. Over-engineering is a kindness. A watch built for 300 metres shrugs at rain, sea swims, the wet commute and a toddler with a tap. You stop thinking about it. The best-built thing you own is the one you never worry about, and that calm feels wonderful on the wrist.

It started honestly. In 1953, Blancpain launched the Fifty Fathoms, arguably the first modern dive watch, developed with Captain Bob Maloubier, who wanted a watch for real dives. Fifty fathoms is about 91 metres, and the people who wore it went there.

Then the numbers climbed, well past anything a recreational diver can use. The dive watch's job quietly changed from surviving the dive to making you feel you could. We think that's a promotion.

We'll be honest. Our Manta and Manta Revelare and our planned Manta Revelare Amethyst carries a 200-metre water-resistance rating. That's five times deeper than a recreational diver goes. Its deepest dive will probably happen in a washing-up bowl. (Take it off first, please. Hot water and steam are tough on seals).

We never built Manta watch range to play submarine. We built it to turn heads: a guilloché dial in Forest Green, Rose Red, Royal Blue, Midnight Black or Sky Blue. We build every Manta to order, so yours is properly yours. It makes the same over-engineered promise every great watch makes: whatever the day throws at you, we've got it — especially if you get even seriously wet!

Here's the bit we mean most.

Bravery doesn't come with a pressure rating.

Edward and Christopher, the two men we named this brand after, each saved a child's life. Nobody tested them in a chamber first. Nobody handed them a number. They were ready when it counted, and that's the only readiness that matters.

So, we rate our watches in metres, and we rate our mission by our and your charitable contributions. Every Edward Christopher® watch triggers a £35 donation to a children's charity that you choose: Operation Orphan or Coram Kidscape. And…you can add your own donation, too. One purchase with an even greater impact for those who need your help.

Tell us where your diver's watch has really been. We're collecting confessions and crowning the most embarrassing deepest dive. Bath entries welcome. We're not monsters.

Fancy a watch that's ready for anything, including the sink? Meet the Manta range. from £1,350: 200-metre water resistance, five colours, free worldwide shipping, a five-year international warranty and £35 to a children's charity of your choice.

Prefer your adventures to be more land-based? The Ripple starts at £975.

Not ready? Join the list and we'll tell you when the next drop lands. Join our community.

Edward Christopher® — named after two brave British men who each saved a child's life.