A genuine Seiko MM300 micro adjust clasp that fits any 18mm bracelet, available for sale.

• Condition: Used, but could pass as new
• Part Number: D1K6AM-BK00
• Fits Bracelet Size: 18mm

This is an excellent and highly collectible example of the modern MarineMaster 300, featuring a Zaratsu-polished case, sapphire crystal, and in-house 8L35 movement. The deep blue dial is luminous and changes character in any light.

• Condition: Excellent with light scratches on case and very minimal on bracelet
• Case size: 44mm
• Lug to lug length: 50mm
• Thickness: 15mm

A Seiko SPB185 with an OEM SPB187 bezel installed, available on bracelet or rubber strap. This watch is a modified version of the MM200 that offers the benefits of the MM300 without its bulk and price.

• Condition: new in box
• Bezel Type: OEM ceramic and steel
• Strap Included: Crafter Blue Curved/Fitted rubber strap
• Bracelet Status: unworn on bracelet

A Seiko MM300 sold in its original box with a sticker.

• Condition: rough shape
• Box Type: original
• Paperwork: none

Up for sale is my Seiko Marinemaster 200M (SJE101) with the black dial. This is the modern, slim Marinemaster powered by the 6L37 movement, offering a much thinner and more wearable case compared to the older MM300 while still delivering true tool-watch capability and excellent finishing.

• Condition: Excellent with light, honest wear
• Movement: 6L37 automatic
• Thickness: 12.3mm thin case profile
• Water Resistance: 200m

This is a Seiko SLA059 housed in the now discontinued MM300 monobloc case, full kit plus an extra strapcode bracelet.

• Condition: Good condition
• Case material: Monobloc case
• Bracelets included: 2
• Shipping options: Free shipping to FedEx store near buyer's address or discuss overseas shipping options

This is an iconic Seiko Prospex MM300, a highly collectible example of the modern MarineMaster 300. It features a Zaratsu-polished case, sapphire crystal, and in-house 8L35 movement running at +3s/day. The deep blue dial is luminous and changes character in any light.

• Condition: Excellent, with some light scratches on case and minimal on bracelet
• Case size: 44mm
• Water resistance: 300m
• Movement: in-house 8L35 (GS base)

The seller is listing a Seiko MM300 monobloc case housing the SLA059 model, which is an unworn timepiece.

• Condition: Unworn
• Case type: Discontinued monobloc case (MM300)
• Shipping options: Free shipping in US to FedEx store; can discuss overseas shipping

This Seiko Marine Master Professional 300m is a high-performance automatic diver's watch with a 44mm case size and Cal. 8L35 movement.

• Condition: Original, unpolished case; light hairlines on crystal, clasp, bracelet, and case
• Case size: 44mm diameter
• Thickness: 14.6mm
• Lug-to-lug: 50mm