Side by side

Serica Ref. 5303 Diving ChronometervsSeiko Prospex Sea 1970 Heritage Diver's Save the Ocean Special Edition

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

Ref. 5303 Diving Chronometer
SericaRef. 5303 Diving Chronometer
MSRP $1,768

At a glance

13 of 29 specs differ
Diameter
Ref. 5303 Diving Chronometer39mm
Prospex Sea 1970 Heritage Diver's Save the Ocean Special Edition42.7mm
Power Reserve
Ref. 5303 Diving Chronometer42h
Prospex Sea 1970 Heritage Diver's Save the Ocean Special Edition70h
Water Resistance
Ref. 5303 Diving Chronometer300m
Prospex Sea 1970 Heritage Diver's Save the Ocean Special Edition200m
MSRP
Ref. 5303 Diving Chronometer$1,768
Prospex Sea 1970 Heritage Diver's Save the Ocean Special Edition$1,350

Full specifications

Case

4 specs
Diameter
39mm
42.7mm
Thickness
12.2mm
13.2mm
Lug-to-Lug
46.5mm
46.4mm
Water Resistance
300m
200m

Crystal & Dial

4 specs
Crystal Shape
Flat
Curved
AR Coating
Yes
Anti-reflective coating on inner surface
Dial Color
Enamel Black
Black
Lume
Super-LumiNova
LumiBrite on hands, index(es) and bezel

Movement

4 specs
Caliber
M100 COSC
6R35
Power Reserve
42h
70h
Jewels
25
24
Complications
COSC
None

Pricing

1 specs
MSRP
$1,768
$1,350

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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.

Serica Ref. 5303 Diving Chronometer

Owners widely praise the Serica Ref. 5303 Diving Chronometer for its excellent wearability, definitive style, and smooth, confident bezel action. The dual scale on the bezel is noted as surprisingly useful, and the crown action, winding, and hacking are reported to work perfectly. One owner describes the Serica 5303-3 as gorgeous and unique, though another notes the crown can appear comically large. On balance, owners rate the Serica Ref. 5303 Diving Chronometer highly for its blend of unique design and robust functionality.

Seiko Prospex Sea 1970 Heritage Diver's Save the Ocean Special Edition

The Seiko Prospex Sea 1970 Heritage Diver's Save the Ocean Special Edition is praised for its beautiful design and refinement over previous models, featuring vertically textured glacier-inspired dials. Owners, however, consider the €1500 RRP too high, suggesting a price closer to €900-€1000, noting the aluminum bezel insert instead of ceramic. Some owners report the 6R movement runs slow. On balance, owners find the Seiko Prospex Sea 1970 Heritage Diver's Save the Ocean Special Edition beautiful and a refinement, but the price and aluminum bezel are points of contention.

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