Side by side

Seiko Prospex Sea 1968 Heritage Diver's GMTvsYema Superman Slim CMM.20

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

Prospex Sea 1968 Heritage Diver's GMT
SeikoProspex Sea 1968 Heritage Diver's GMT
MSRP $1,500
Superman Slim CMM.20
YemaSuperman Slim CMM.20
MSRP $2,372

At a glance

12 of 29 specs differ
Diameter
Prospex Sea 1968 Heritage Diver's GMT42mm
Superman Slim CMM.2039mm
Power Reserve
Prospex Sea 1968 Heritage Diver's GMT72h
Superman Slim CMM.2040h
Water Resistance
Prospex Sea 1968 Heritage Diver's GMT200m
Superman Slim CMM.20300m
MSRP
Prospex Sea 1968 Heritage Diver's GMT$1,500
Superman Slim CMM.20$2,372

Full specifications

Case

5 specs
Diameter
42mm
39mm
Thickness
12.9mm
9.95mm
Lug-to-Lug
48.6mm
Material
Stainless Steel
316L Stainless Steel
Water Resistance
200m
300m

Crystal & Dial

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

Movement

3 specs
Caliber
6R54
Yema CMM.20
Power Reserve
72h
40h
Jewels
24
25

Pricing

1 specs
MSRP
$1,500
$2,372

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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 Sea 1968 Heritage Diver's GMT

The Seiko Prospex Sea 1968 Heritage Diver's GMT is widely praised for its build quality, finishing, and comfortable wearability, offering good value for its price point. Owners and reviewers highlight the attractive silver/white sunray dial, blue ceramic bezel, and the premium feel of the improved bracelet clasp with excellent micro-adjustment. The Caliber 6R54 movement provides a 72-hour power reserve, and real-world accuracy often exceeds its stated range of +25 to -15 seconds per day, with some owners reporting figures around +3 to +5 seconds per day. However, the caller-style GMT functionality is a point of contention for some, who find the GMT scale difficult to read and prefer a flyer GMT at this price. Some also find the crown position at 4 o'clock undesirable, and a few note a lack of dial contrast or illegibility of the inner bezel.

Yema Superman Slim CMM.20

Owners and reviewers praise the Yema Superman Slim CMM.20 for its appealing retro design, balanced 39mm case, and in-house CMM.20 micro-rotor movement, with some finding the fish scale bracelet attractive. Concerns exist regarding its $2500/€2,490 MSRP, with some owners questioning its value and noting the potential for QC issues or a "jittery" seconds hand attributed to the new movement. The bracelet's articulation and stamped clasp draw criticism, though some owners report it improves with wear. Overall, owners and reviewers appreciate the Yema Superman Slim CMM.20's vintage styling and unique micro-rotor movement, but its value proposition and some finishing details are points of contention.

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