Which is cheaper, the Helgray Poseidon Diver (Automatic) or the Seiko Prospex Sea The Black Series?

At MSRP the Helgray Poseidon Diver (Automatic) is the cheaper of the two at $249, against $765 for the Seiko Prospex Sea The Black Series — a $516 gap before any retailer discounting.

Which is bigger, the Helgray Poseidon Diver (Automatic) or the Seiko Prospex Sea The Black Series?

The Seiko Prospex Sea The Black Series wears larger at 45mm versus 40mm for the Helgray Poseidon Diver (Automatic) — a 5mm difference across the dial.

Which has better water resistance, the Helgray Poseidon Diver (Automatic) or the Seiko Prospex Sea The Black Series?

The Helgray Poseidon Diver (Automatic) is rated to 300m versus 200m for the Seiko Prospex Sea The Black Series.

Which has a longer power reserve, the Helgray Poseidon Diver (Automatic) or the Seiko Prospex Sea The Black Series?

The Seiko Prospex Sea The Black Series carries a 41-hour power reserve against 40 hours on the Helgray Poseidon Diver (Automatic).

What movement does the Helgray Poseidon Diver (Automatic) run compared to the Seiko Prospex Sea The Black Series?

Both watches run automatic movements — the Helgray Poseidon Diver (Automatic) uses the NH35 Warranty and the Seiko Prospex Sea The Black Series uses the 4R36.

Side by side

Helgray Poseidon Diver (Automatic)vsSeiko Prospex Sea The Black Series

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

Helgray Poseidon Diver (Automatic)

poseidon-diver-automatic

MSRP $249

Seiko Prospex Sea The Black Series

srpk43

MSRP $765

At a glance

11 of 29 specs differ

Diameter

Poseidon Diver (Automatic)40mm

Prospex Sea The Black Series45mm

Power Reserve

Poseidon Diver (Automatic)40h

Prospex Sea The Black Series41h

Water Resistance

Poseidon Diver (Automatic)300m

Prospex Sea The Black Series200m

MSRP

Poseidon Diver (Automatic)$249

Prospex Sea The Black Series$765

Full specifications

Case

5 specs

Diameter

40mm

45mm

Thickness

12mm

13.2mm

Lug-to-Lug

46mm

47.7mm

Lug Width

20mm

22mm

Water Resistance

300m

200m

Crystal & Dial

2 specs

AR Coating

Inner

Anti-reflective coating on inner surface

Lume

None

LumiBrite on hands, index(es) and bezel

Movement

3 specs

Caliber

NH35 Warranty

4R36

Power Reserve

40h

41h

Jewels

Pricing

1 specs

MSRP

$249

$765

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