A 300-metre diver with the whole calendar on it.

Blancpain’s complete calendar, day, month, pointer date and moon, has lived on the Villeret dress watches for decades, with correctors under the lugs so you can set it without a tool. The Bathyscaphe version moves the whole thing into a 300-metre case with a ceramic bezel, and the point is simple: a diver you can wear every day that also tells you the date without a squint, because the date is read by a hand rather than through a window.

The rest is Bathyscaphe: luminous dots and batons, a ceramic bezel with markers in Liquidmetal alloy that cannot fade, and a grey dial that keeps the calendar readable. The 6654.P inside has a silicon balance spring and three days of reserve, so the calendar keeps running through a long weekend off the wrist.

This is a regular Amazon listing from a marketplace seller with Amazon’s 30-day return window; it is not a Luxury Stores unit and the seller has not published a condition. The second button opens the live search for Bathyscaphe calendars in case this one has sold.

Bathyscaphes have resold for under new and close to what pre-owned buyers paid, sometimes more, sometimes less; that is a pattern, not a promise, and nothing here is investment advice.