Automatic Movement

This watch has an exhibition back made of Seiko's Hardlex crystal through which you can see something of the the inner workings. This 7S36C movement is far from being the most expensive, intricate, highly decorated or technically advanced, but it (and its close design relatives) may legitimately hold claim to being among the most robust and proven mechanical watch mechanisms ever designed - given its record of performance over more than 20 years of production. Timepieces using this series of movements have routinely run for 10-15 years or more, all the while keeping excellent time, without any servicing.