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Seiko Prospex Marinemaster Marinemaster 1968 Heritage Diver's WatchvsRGM Watches Model 300 Divers

The numbers, the dial colors, the calibers — laid out so you can stop flipping between tabs.

What people say

Owners + reviewers, side by side

Synthesized for each watch independently from owner discussions, enthusiast forums, written reviews, and video reviewers.

Seiko Prospex Marinemaster Marinemaster 1968 Heritage Diver's Watch

The Seiko Prospex Marinemaster 1968 Heritage Diver's Watch is widely praised for its excellent quality and finishing, with reviewers and owners noting its GS-level craftsmanship and Zaratsu-inspired polishing. Owners appreciate its refined design, comfortable case shape, and the 4:00 crown position, with some finding it more manageable on the wrist than other models. The Caliber 8L45 movement offers a 72-hour power reserve and accuracy within -5/+10 seconds per day, and the bracelet features an improved clasp with an extension system. However, some find the price point high, and one reviewer noted the unsigned winding crown as a missed opportunity. On balance, owners and reviewers rate the Seiko Prospex Marinemaster 1968 Heritage Diver's Watch highly for its premium finishing and tool-like appearance at its price point.

RGM Watches Model 300 Divers

Owners widely praise the RGM Watches Model 300 Divers for its outstanding quality, typical of RGM, and its rugged, cool appearance. Some owners note its 17mm thickness and small dial, with one comparison suggesting its quality does not match that of Omega. The watch is available with a bracelet in outstanding condition and an OEM rubber strap showing minor wear. On balance, owners rate the RGM Watches Model 300 Divers highly for its build quality and distinctive aesthetic.

At a glance

13 of 29 specs differ
Diameter
Prospex Marinemaster Marinemaster 1968 Heritage Diver's Watch42.6mm
Model 300 Divers43.5mm
Power Reserve
Prospex Marinemaster Marinemaster 1968 Heritage Diver's Watch72h
Model 300 Divers40h
Water Resistance
Prospex Marinemaster Marinemaster 1968 Heritage Diver's Watch300m
Model 300 Divers762m
MSRP
Prospex Marinemaster Marinemaster 1968 Heritage Diver's Watch$3,600
Model 300 Divers$4,450

Full specifications

Case

6 specs
Category
Diver
Diameter
42.6mm
43.5mm
Thickness
14.1mm
17mm
Lug-to-Lug
49.3mm
46mm
Lug Width
20mm
22mm
Water Resistance
300m
762m

Crystal & Dial

3 specs
Crystal Shape
Curved
Flat
AR Coating
Anti-reflective coating on inner surface
Inner
Lume
LumiBrite on hands, index(es) and bezel
None

Movement

3 specs
Caliber
8L45
Sellita SW300-1
Power Reserve
72h
40h
Jewels
35
25

Pricing

1 specs
MSRP
$3,600
$4,450
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