To mark the 10th birthday of its instant-classic J12 watch, Chanel takes the plunge — to 300 meters, in fact — and brings would-be Cousteaus the J12 Marine. Chanel’s new undersea timepiece for gents has a list of features that would make even an octopus dizzy: a shot-peened case; hands coated in “Ocean Blue” ceramic (they glow so you can see them down there in the dark); and a rubber-composite strap that fends off scratches, shocks, water and UV rays. It adds up to one tough ticker — “practical, accurate, harshly simple,” they explain at Chanel, “like the men’s watches that Miss Chanel liked to borrow from her lovers.” (Seems marriage was the one plunge Coco didn’t care to take.) J12 Marine, at the Chanel boutique.