Introducing the next generation of the Seiko Prospex “20MAS” – now smaller and with a new movement (SPB453, SPB451 and SPB455)

If we stick to nickname conventions, these 2024 divers will be the “24MAS,” and Seiko is launching the new model line with a trio that includes the SPB453 (black), the SPB451 (blue), and the special edition SPB455, which features an anthracite dial and bezel matched with gold accents for the bezel, hands and numerals. All three models have identical specifications: 40mm wide, 13mm thick and 46.4mm lug to lug. For those who chose the SPB143, the new models are 0.5mm narrower, 0.2mm thinner and 1.2mm shorter from lug to lug – minor improvements in every sense of the word.

Despite being smaller in all three main dimensions, these 2024 models increase water resistance from 200 to 300 meters. This is thanks to a revised caseback design that is both thinner and sturdier.