To fit Seiko case numbers
6138-0010, 6138-0011, 6138-0012, 6138-0017, 6138-0019, 6138-0020, 6138-0030, 6138-0031
6138-0040, 6138-0048, 6138-0049, 6139-7000, 6139-7001, 6139-7002, 6139-7010, 6139-7011, 6139-7012, 6139-7020,
6139-7060, 6139-7069, 6139-7149T
34.0mm outside diameter
32.7mm inside diameter
Height 2.40mm