Which is cheaper, the Sheffield Deep Gray 300 or the Seiko Prospex Sea?

At MSRP the Sheffield Deep Gray 300 is the cheaper of the two at $258, against $900 for the Seiko Prospex Sea — a $642 gap before any retailer discounting.

Which is bigger, the Sheffield Deep Gray 300 or the Seiko Prospex Sea?

The Sheffield Deep Gray 300 wears larger at 42mm versus 41mm for the Seiko Prospex Sea — a 1mm difference across the dial.

Which has better water resistance, the Sheffield Deep Gray 300 or the Seiko Prospex Sea?

The Sheffield Deep Gray 300 is rated to 300m versus 200m for the Seiko Prospex Sea.

Which has a longer power reserve, the Sheffield Deep Gray 300 or the Seiko Prospex Sea?

The Seiko Prospex Sea carries a 70-hour power reserve against 40 hours on the Sheffield Deep Gray 300.

What movement does the Sheffield Deep Gray 300 run compared to the Seiko Prospex Sea?

Both watches run automatic movements — the Sheffield Deep Gray 300 uses the Seiko NH35 and the Seiko Prospex Sea uses the 6R35.

Side by side

Sheffield Deep Gray 300vsSeiko Prospex Sea

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

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Sheffield Deep Gray 300

deep-gray-300

MSRP $258

Seiko Prospex Sea

spb317j1

MSRP $900

At a glance

14 of 29 specs differ

Diameter

Deep Gray 30042mm

Prospex Sea41mm

Power Reserve

Deep Gray 30040h

Prospex Sea70h

Water Resistance

Deep Gray 300300m

Prospex Sea200m

MSRP

Deep Gray 300$258

Prospex Sea$900

Full specifications

Case

6 specs

Crystal & Dial

4 specs

Crystal Shape

Flat

Curved

AR Coating

Inner

Anti-reflective coating on inner surface

Dial Color

—

Black

Lume

None

LumiBrite on hands, index(es) and bezel

Movement

3 specs

Caliber

Seiko NH35

6R35

Power Reserve

40h

70h

Jewels

Pricing

1 specs

MSRP

—

$900

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Sheffield Deep Gray 300vsSeiko Prospex Sea

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