Is the SRPD51K1 a true dive watch?

No. It has dive-watch styling, a rotating bezel and 100 m water resistance, but no screw-down crown or ISO diver rating. It handles swimming and daily wear, not serious diving.

Does it have a mechanical or quartz movement?

It uses Seiko's 4R36 automatic mechanical movement. It winds from wrist motion or by hand, hacks when the crown is pulled, and has about 41 hours of power reserve.

What is the case size?

The stainless steel case is about 42.5 mm across and roughly 13 mm thick. That wears large on slim wrists, so try one on if you can.

Does it show the day and date?

Yes. There is a day-date window at 3 o'clock showing both the day of the week and the date.

What comes in the box?

The watch on its stainless steel bracelet, in standard Seiko packaging. Special and limited editions also ship in standard packaging.

How does it compare with a Seiko Prospex diver?

The Prospex line adds sapphire crystal, higher water resistance and often better bracelets. The 5 Sports keeps the same automatic movement family and solid build at a lower tier of finish.