Seiko 5Y01-5020 Watch Guide The Seiko 5Y01-5020 is a watch model based on the 5Y01 movement.Parts ListSADN16JM01crystal35R34NA1crown - crown0H2600N01case back gasket - case back gasketOther models with the same movement5Y01-50005Y01-50105Y01-50305Y01-5040