Seiko Seiko BK63

The Seiko BK63 is a quartz meca-quartz chronograph movement manufactured by Seiko. As a hybrid caliber, it combines quartz timekeeping accuracy with mechanical chronograph functionality, featuring a smooth sweeping seconds hand and instant reset capability. The movement is not produced in-house by Seiko but is supplied to external brands. It remains in production and is used in select Nezumi Studios chronograph models.