Here we have a 2023 Seiko Prospex 'Astrolabe' SLA065J1 Limited Edition of 1300 pieces, as part of their “Save the Oceans” line of dive watches that help to fund global conservation and the removal of damaging rubbish from our oceans. The 41mm stainless steel case is protected by a Seiko proprietary Super hard coating that curves in all the right places towards the drilled lugs, taking its inspiration from the original 1965 62MAS, which was worn by the members of the Japanese Antarctic Expedition between 1966 and 1969. A lug-to-lug length of 47mm and a case thickness of 13mm give the watch an impressive wrist presence. Zaratsu polished bevel-edge transitions perfectly along the flanks of the case; the same master polishing is applied to the unidirectional bezel, and a blue 60-minute insert has deeply engraved numerals and baton markers holding a double-domed sapphire crystal above a deep blue patterned dial. An outer minute chapter ring is precisely executed with applied baton indexes coated in LumiBrite, marking the hours, at 3 o’clock, a date window. The pattern on the dial resembles an ancient “Astrolabe” once used to show the positions of the sun and stars to enable sailors to measure latitude and time to help them navigate the world's oceans. Thick steel sword hands are infilled with LumiBrite and complemented by a counterweighted sweeping second-hand. At 12 o’clock, the Seiko motif, and at 6 o’clock, the Prospex logo “Automatic Divers 200m” is printed underneath, completing this professional dive tool watch. On the reverse, a screw-down case back with the Seiko Tsunami embossed in the centre, inside an automatic Seiko Cal. 8L35, 26 jewels, 28,800 beats per hour, based on the Grand Seiko calibre 9S55, hand-assembled at their Shizuku-ishi Watch Studio in Morioka, Japan. The watch comes fitted on its Seiko 20mm blue silicone strap with a signed buckle, plus a 20mm MILTAT bracelet, two clasps and all links are provided, and the watch comes with its  Seiko presentation box, swing tag and paperwork.