Seiko Bell-Matic 4006 parent reference 4006, grouping exact caliber-case child references 4006-6001, 4006-6002, 4006-6010, 4006-6011, 4006-6021IN, 4006-6031, 4006-6037, 4006-6040, 4006-6060, 4006-7000, 4006-7001, 4006-7010.