The Baby Marinemaster introduced in 2018 brought a 44mm stainless case (51mm lug to lug) with 200 meters of water resistance. Like the Marinemaster 300, its case features a DiaShield hard coating and a sapphire crystal. The bezel makes do with a high gloss painted material that we’re guessing is aluminum underneath. The mid-grade 6R15 brings 50 hours of power reserve along with -15 to +25 seconds of accuracy per day. Most importantly, this series of watches comes in at a skinny minny 13.1mm in thickness.
In the later part of 2020 Seiko outdid itself by launching the reduced sized MM200. The SPB185 features a matte black dial and a utilitarian brushed stainless steel bezel. Black dials are far from uncommon, but Seiko rarely produce dive watches with steel bezels, giving this an exciting look from the watchmaker. In contrast, the SPB187 is equipped with a black aluminium bezel that is much more in line with the rest of Seiko’s dive watches, and a sunburst brushed blue dial. When the SPB077 had a 44mm x 13.1mm case, these new models are 42mm in diameter with a height of 12.5mm. The 2mm less is not neglectable and can properly be felt on the wrist. Both the Seiko Prospex SPB185 and SPB187 are powered by the in-house automatic calibre 6R35, which is the movement of choice for most mid-range Seiko dive watches. It features 70 hours of power reserve, and also has a handy date function. As new permanent members of the Seiko Prospex range, these watches hit the sweet-spot of heritage inspiration while still feeling thoroughly modern in their design and execution.