AndCavanaugh
515
It's based on the Soprod A-10, it is the thinnest Seiko automatic and the only men's automatic currently used by Credor
Before this Credor used 8L (lower grade version of GS Seiko 9S) and 4S (52 stream) movements. The 8L is very thick (~6 mm) and 4S is middle of the road (~4 mm). In 2005 they launched models with 4L (3.6 mm) movements--which were likely made from Soprod ebauches.
While it isn't very fancy it's slimness makes it the best fit for the Credor brand. Seiko started producing its own version in-house sometime before 2017, which is the 6L (2.7 mm). There is a long tradition of Credor movements being gilt instead of rhodanized, which explains the finish.