Seiko SPB143 strap size and lug width
What fits the SPB143 and its 1965 Heritage Diver's successors, from Seiko's published specs.
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The short answer
The SPB143 takes 20 mm straps. Seiko lists a 40.5 mm case, 47.6 mm lug-to-lug and 13.2 mm thickness; it ships on a bracelet. Its successors, the SPB451 and SPB453, are also 20 mm, so the same straps fit all three.
| SPB143 | Prospex | 20 mm | 40.5 mm | 47.6 mm | 13.2 mm | Bracelet | – |
| SPB451 | Prospex · Sea | 20 mm | 40 mm | 46.4 mm | 13 mm | Bracelet | – |
| SPB453 | Prospex · Sea | 20 mm | 40 mm | 46.4 mm | 13 mm | Bracelet | – |
Click a column heading to sort. n/p = not published by the brand. Quick-release "Yes" only where the brand page says so; "–" means not stated, not "no".
Which strap type?
- Rubber or silicone: the practical choice for swimming and hot weather. It doesn't absorb water and rinses clean.
- Fabric single-pass or two-piece nylon: light and cheap. A single-pass strap runs under the case, which adds a little height on the wrist.
- Leather: dressier, but water and sweat shorten its life. Keep it off dive watches you actually swim with.
- Steel bracelet: the most durable, but aftermarket bracelets need end links shaped for the specific case, which brands rarely publish. Buy one listed for your exact reference.
Spring bars: what Seiko doesn't publish
Seiko lists lug width, but not spring-bar diameter or a strap code. Aftermarket straps vary in how large their spring-bar holes are, so before you buy, check the strap's stated hole size against the bars you'll use, or reuse the original bars if they fit. See our spring bars and tools guide.
Shop straps
Paid links to Amazon search results. Check the listed width and spring-bar hole size against the table above.
Questions
What size strap does the SPB143 take?
20 mm, per Seiko's product page.
What is the SPB143 lug-to-lug?
47.6 mm, per Seiko's product page (Philippines site, checked October 2026).
Will SPB143 straps fit the SPB453?
Yes, both are 20 mm. The SPB453 is shorter lug-to-lug (46.4 mm), so a strap will sit slightly differently, but the width matches.
What spring bars does the SPB143 use?
Seiko doesn't publish the spring-bar diameter. Reuse the original bars, or check the strap's hole size before buying.
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