Side by side

Serica Ref. 5303 Diving ChronometervsSeiko Prospex Sea 1970 Heritage Diver's Black Series Limited 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 Black Series Limited Edition44mm
Power Reserve
Ref. 5303 Diving Chronometer42h
Prospex Sea 1970 Heritage Diver's Black Series Limited Edition50h
Water Resistance
Ref. 5303 Diving Chronometer300m
Prospex Sea 1970 Heritage Diver's Black Series Limited Edition200m
MSRP
Ref. 5303 Diving Chronometer$1,768
Prospex Sea 1970 Heritage Diver's Black Series Limited Edition$3,300

Full specifications

Case

4 specs
Diameter
39mm
44mm
Thickness
12.2mm
13mm
Lug-to-Lug
46.5mm
49.3mm
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
8L35
Power Reserve
42h
50h
Jewels
25
26
Complications
COSC
None

Pricing

1 specs
MSRP
$1,768
$3,300

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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 Black Series Limited Edition

Owners widely praise the Seiko Prospex Sea 1970 Heritage Diver's Black Series Limited Edition for its attractive, well-made design and gorgeous dial, noting its jewel-toned teal color and rippling-water pattern. The bezel action is smooth with a muted sound, and the case and bracelet offer a more comfortable feel than previous iterations. However, multiple owners express disappointment with the accuracy of the 6R movement at its price point, with some noting theirs runs slow, and consider the price too high. The steep rehaut and marker size make the 24-hour numbers difficult to read, and some find the case design makes the watch feel top-heavy despite wearing smaller. Overall, owners rate the Seiko Prospex Sea 1970 Heritage Diver's Black Series Limited Edition highly for its striking dial and refined case design, despite concerns regarding movement accuracy at its price.

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