Seiko Y121-X156 Watch Guide The Seiko Y121-X156 is a watch model based on the Y121 movement.Other models with the same movementY121-0AA0Y121-0AD0Y121-8A40Y121-X099Y121-X103Y121-X117Y121-X118Y121-X120Y121-X121Y121-X122Y121-X125Y121-X126Y121-X128Y121-X130Y121-X132Y121-X133Y121-X134Y121-X136Y121-X137Y121-X138Y121-X139Y121-X140Y121-X141Y121-X142Y121-X144Y121-X145Y121-X148Y121-X150Y121-X151Y121-X152Y121-X153Y121-X154Y121-X155Y121-X157Y121-X160Y121-X161Y121-X165