Seiko Turtle vs Seiko 5 Sports

The step past both: a 300m diver's watch with sapphire and a 72-hour 6R55 with a published accuracy tolerance, in a 40mm case with a 46.4mm lug-to-lug.

Two tiers above the Turtle, with a $296 published overhaul.

300m and a 46.4mm lug-to-lug in the same watch is unusual. The extender in the clasp is the detail that says Seiko still expects this one to be dived, not just worn.

A genuine diver's watch — a screw-down crown, a screw case back, a unidirectional bezel and the ISO 6425 marking — on the 4R36 and a published $176 overhaul.

Seiko's 45mm figure overstates it: the cushion case has no protruding lugs.

Seiko rates this at 200m as a diver's watch, not merely water-resistant — screw-down crown, screw case back, unidirectional bezel. The 45mm figure is misleading: the cushion case has no protruding lugs.

The same movement, crystal, thickness, warranty and service price in a 42.5mm case with a 46mm lug-to-lug, one tier down.

Rated 100m with no diver's marking — fine for swimming, not for diving.

The 4R36 is the most commonly serviced mechanical caliber in the United States and Seiko publishes a flat $176 price to overhaul it. That single fact does more for a twenty-year horizon than any spec on the case.

The SRPD55's case with a hard coating that takes the first scuffs, on a nylon strap — 94g on the wrist instead of 170g.

The same 100m, and no diver's marking.

Same 4R36 and the same $176 published service price as every other 5 Sports, with a hard coating on the case that takes the first year of scuffs instead of the steel.