Seiko Prospex
SLA021 300m Diver

Seiko Prospex Marine Master 300m SLA021 Watch Review

The Seiko professional diver SLA021 watch comes with a stainless steel bracelet. The 021 has exceptional capability and is substantial. It is 44.3mm in diameter and 15.3mm thick. It is 50.2mm lug to lug, but if you include the solid end links of the bracelet then it is 52.8mm across the wrist with a highly orthodox and versatile 20mm spacing between the lugs. This watch is more substantial than standard Seiko divers. It is best suited for a wrist of 15cm circumference or larger, but a smaller wrist could wear this watch comfortably.

The Hardware

This timepiece has a steel bracelet with a staggered link alignment and finish, satin primaries, polished out faces, and polished intermediates. There are pins and sleeves used for sizing the bracelet that are removable, so there is quite a bit of built-in room for adjustments. The clasp also has four drilled divots, so you can use your strap tool to change the anchoring point to the bracelet inside the clasp.

When you lift up the extension system, it allows you to incrementally extend the dive fold outward. If it's on your wrist and you're underwater it is just as easy to manipulate. It can fold out over a dive suit with its trigger release system; alternatively there is also a clamshell lick.

There are two strap holes in the flanks of the lugs on the case. The case is a monoblock, which means everything loads through the front. There is no discrete removable case back. This watch is so hermetically sealed that even helium can't get in, so this watch is suitable for saturation divers.

The case band has polished elements that are black and mirrored. The bezel is chunky and deeply knurled with a beautiful combination of silky refinement and mechanical detente. It has a ceramic bezel insert, and you will notice in the loom shot that the bezel is luminous from the index through 20 minutes. The dial features applique indices and lovely satin finished hands. All three hands loom like they should on any dive watch. The crystal in this watch is sapphire, and the crown is a screw-down 300.

The Movement

The movement is 8L35b, which is a Grand Seiko movement with a lower level of exterior finish and adjustment. It has a 50 hour automatic winding power reserve and a stop-seconds function, so you can set it precisely. It has a quick set date and 26 jewels.

The Seiko Prospex Diver Professional SLA021 has a DiaShield outer hard coating on its Zaratsu polished surface wallet. It is a handsome execution, and it is also very tough. The watch is substantial and durable and is a watch you will want to wear all the time.