Seiko introduced the 62MAS in 1965 and it was THE original professional dive watch from the Japanese company. The nickname "62MAS" comes from the first two digits of the reference number – 62 – and MAS from "auto[MA]tic [S]elfdater," AKA an automatic movement with date. In 2017 Seiko recreated these into modernized versions with sapphire crystals, 6R15 movements which has about 50 hours of power reserve for most versions (except for SLA017 which has an 8L movement). The Cases and Bracelets are protected with a super-hard coating. Seiko refers to this as their ‘DiaShield’ treatment so scratching the surfaces should not be very easy. The 2020 recent releases have upgraded 6R35 automatic movements, coupling a hefty 70-hour power reserve with a slow and steady 21,600 bph beat rate. The Case size has also been reduced for a better wrist fit at a 40.5mm diameter and 48mm lug-to-lug, on paper this watch seems like a rather standard midsize diver. As with so many modern Seiko cases, however, these numbers can be deceiving, as clever case geometry helps this one to feel old-school compact on the wrist and far slimmer than the 15mm thickness would imply. While the simple skin diver case style and oversized unguarded screw-down crown might feel straight from the ’60s, Seiko sets these models apart with thoroughly modern attention to detail.