Part Number: 389243-00 389244-00. Package Includes: as images show, Cut-Out Tool Collet Kit (4 Pck). Size: collet 1/8" ,3.0mm 1/4". Compatible With: Dewalt DW660S Type 1 Cut Out Tool,DW660S Type 2 Cut Out Tool,DW660S Type 3 Cut Out Tool,DW660 Type 1 Cut Out Tool,DW660 Type 2 Cut Out Tool,DC550A Type 1 18V Cordless Cut Out Tool,DC550W Type 1 Cut Out Tool,DC551 Type 1 Cut Out Tool,DW660SK Type 1 Cut Out Tool Kit,DW660SK Type 2 Cut Out Tool Kit,DW660SK Type 3 Cut Out Tool Kit,DC550P Type 1 18V Cut Out Tool,DC550K Type 1 18V Cut Out Tool,DC550KA Type 1 18V Cut Out Tool,DC550P (Type 1) Heavy Duty 18V Cordless Cut-Out Tool,DW660K (Type 1) Cut Out Tool Kit,DW660K (Type 3) Cut Out Tool Kit,DCS551B (Type 1) 20v Crdls Cutout Bar,DCS551B (Type 2) 20v Crdls Cutout Bar,DCS551D2 (Type 1) 20v Cordelss Cutout. it is also fit to Ryobi Collet 1/4 Inch - 690045003 530 SS50K P531 P601 Palm Router.