This is the screw-back case back for the 10th-anniversary model of the Casio G-Shock by CASIO. DW-1983 It should fit screw-back models of the 5600 series. It was successfully fitted on a DW-5600. - Brand: CASIO - Model: 10th Anniversary - Material: Stainless Steel - Year: 1983 - Water Resistance: Water Resistant - Special Features: Commemorative Model Thank you for looking.