AddiesdiveMY-H7
Homage to the Seiko Prospex Marinemaster 300
about$139
Regular price at addiesdivewatches.com, checked 31 Oct 2026. Marketplace prices change often.
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The Addiesdive MY-H7 is a homage to the Seiko Prospex Marinemaster 300, with a 44 mm case, 1.4 mm larger. It uses an automatic movement and is water resistant to 300 m. It costs about $139 at the official store.
Side by side with the original
Compared with reference SLA079J1. Values marked ≈ are estimates, such as a reviewer's measurement.
| Spec | MY-H7 | Marinemaster 300 (SLA079J1) | Difference |
|---|---|---|---|
| Case diameter | 44 mm | 42.6 mm | +1.4 mm |
| Lug-to-lug | Not published | 49.3 mm | Can't compare |
| Thickness | 17 mm | 13.4 mm | +3.6 mm |
| Lug width | 20 mm | 20 mm | same |
| Water resistance | 300 m | 300 m | |
| Movement | Automatic, NH35A | Automatic, 8L35 | |
| Power reserve | 41 h | 50 h | |
| Crystal | Sapphire | Sapphire, anti-reflective coating on inner surface | |
| Bezel | Rotatable bezel, Ceramic | Unidirectional rotating | |
| Case material | 316L stainless steel | Stainless steel | |
| Lume | BGW9 blue lume on hands | LumiBrite on hands, indices and bezel | |
| Bracelet | Steel bracelet | Steel bracelet | |
| Weight | Not published | 196 g |
The original
Seiko
Marinemaster 300
Reference SLA079J1, 1968 heritage diver's watch, black dial
- Case
- 42.6 mm
- Lug-to-lug
- 49.3 mm
- Thickness
- 13.4 mm
- Water resistance
- 300 m
- Movement
- Automatic, 8L35
- List price
- $2,900
Why it scores as it does
Proportions and movement are computed from specs. Design details and functions are judged from the brand's official images. How we score
Lug-to-lug is neither published nor measured for one of the two watches, so there is not enough data to score.
Proportions— / 30
- Case diameter6.4 / 121.4 mm apart
- Lug-to-lug0 / 8Not published, left out
- Thickness0 / 63.6 mm apart
- Lug width4 / 4Same size
Design signatures— / 40
- Broad, faceted hour and minute hands8 / 8Broad lume-filled hour and minute hands with a faceted look.
- Steel unidirectional bezel with black insert and lumed triangle4 / 8Rotating bezel with a lume triangle at 12, but a green or blue ceramic insert instead of steel with a black insert.
- Screw-down crown at 4 o'clock7 / 7Screw-down crown at 4.
- Round lume plots with rectangular 3, 6 and 9 and a double-width 123.5 / 7Round lume plots with rectangular markers at 6 and 9 and a double-width marker at 12; the 3 o'clock position holds the date window.
- Fine sand-like textured dial0 / 4Smooth sunburst dial; no sand-like texture.
- Mixed-finish case with strong facets1.5 / 3Brushed and polished case with angular flanks; fewer facets than the original.
- Bracelet of three broad brushed links with narrow polished links between1.5 / 3Steel bracelet with broad links; the narrow polished links between are hard to see in the images.
Functions and materials— / 20
- Complications8 / 8Time with sweep seconds and a date, as on the original.
- Bezel action2 / 4Rotatable bezel; the brand does not say if it is unidirectional. The original is unidirectional.
- Case and bezel materials2 / 4316L steel case with a ceramic bezel insert; the original's bezel is steel.
- Crystal shape and date window4 / 4Sapphire curved on both sides with no cyclops; the original is sapphire.
Movement type— / 10
- Movement type10 / 10Same movement type.
What reviewers and owners say
We haven't read enough independent reviews of this model to summarise them yet.
Good
- Broad lume hands and plot layout close to the original's
- Domed sapphire on both sides
- 300 m water resistance
- Green and blue colourways
- Signed crown and caseback
Less good
- Brand thickness of 17 mm looks high and is not confirmed
- Coloured ceramic bezel instead of steel with a black insert
- No lug to lug published
Versions and colours
- Green dial and bezelIts own colourway, not on the originalabout $139
- Blue dial and bezelIts own colourway, not on the originalabout $139
Compare
Sources
Checked 31 Oct 2026. Every figure on this page comes from one of these pages.