Century Chronometer - L4.721.2 JDM You are looking at a

You are looking at a magnificent statement from the peak of Seiko's experimental era: the Seiko Advan

thereby reducing lubricant breakdown and friction on the automatic movement for superior chronometer precision

13mm (including faceted crystal) BETWEEN LUGS 18mm SERVICE Running - Service History Unknown STRAP Stainless Steel Bracelet (Original style)

Flipping the watch over reveals the crisp caseback engraving with the reference and the serial number 060410

Century Chronometer - L4.721.2 JDM You are looking at aYou are looking at a watch built on a scientific principle! The incredible selling point here is the "VACUUM" construction. Century's founder, Hans Ulrich Klingenberg, patented a system in the 1960s to literally evacuate the air from the watch case, then seal it to create a vacuum. This wasn't for water resistance (though it is waterproof); the core purpose was to eliminate moisture, dust, and, crucially, oxygen, thereby reducing lubricant breakdown