Side by side

Tudor Black Bay One 31 S&GvsZelos Helica Moonphase

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

Black Bay One 31 S&G
TudorBlack Bay One 31 S&G
MSRP $6,850
Helica Moonphase
ZelosHelica Moonphase
MSRP $1,049

At a glance

12 of 29 specs differ
Diameter
Black Bay One 31 S&G31mm
Helica Moonphase39mm
Power Reserve
Black Bay One 31 S&G50h
Helica Moonphase40h
Water Resistance
Black Bay One 31 S&G100m
Helica Moonphase100m
MSRP
Black Bay One 31 S&G$6,850
Helica Moonphase$1,049

Full specifications

Case

8 specs
Category
Moonphase
Diameter
31mm
39mm
Thickness
9.5mm
10mm
Lug-to-Lug
46mm
39mm
Lug Width
17mm
20mm
Material
Stainless Steel
316L Stainless Steel
Finish
Polished + Satin
Brushed and polished
Caseback
Solid screw-down
Solid

Crystal & Dial

1 specs
Dial Color
Black
Meteorite

Movement

2 specs
Caliber
MT5201
Sellita SW288 Moonphase
Power Reserve
50h
40h

Pricing

1 specs
MSRP
$6,850
$1,049

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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.

Tudor Black Bay One 31 S&G

The Tudor Black Bay One 31 S&G is praised for its quiet luxury, combining brushed steel and warm gold accents for understated charm. Owners appreciate the brushed gold for a casual two-tone look and the champagne dial's surprising legibility. Some find the case sides too thick, and one user expressed a desire for a smaller S&G variant. The watch features the MT5612 movement with a 70-hour power reserve and a date function, within a 200-meter water-resistant case. Overall, owners and reviewers highlight the Tudor Black Bay One 31 S&G's balanced two-tone aesthetic as its primary appeal.

Zelos Helica Moonphase

Owners widely praise the Zelos Helica Moonphase for its gorgeous aventurine dial, unique industrial-dress aesthetic, and comfortable wearability, with one owner calling it spectacular and another their favorite Zelos. The moonphase complication is frequently highlighted as beautiful, though some find the double moon distracting or the dial cluttered. A manual-wind movement combined with a screw-down crown is noted as a drawback by some, requiring adjustment and potentially feeling fragile when fully wound, while one owner reports a 43-hour power reserve. On balance, owners rate the Zelos Helica Moonphase highly for its stunning aventurine dial and unique design at its price point.

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