Perfectly Fitment: Used on Annovi Reverberi RK, RKA, RKV, XRCA, XRV, XRCV series pressure washer pumps (also known as AR pumps.) (Please check parts size before ordering.) Directly Replacement: Directly replaces manufacturers part AR2546 Package Included: 3 x Ceramic Pistons; 3 x Copper Washers; 3 x Spacers; 3 x O-Rings; 3 x Piston Nuts; 3 x Backup Rings Ceramic Pistons Dimensions: 18mm OD, 11mm ID, 40mm length AR2546 Pump Piston Kit Ceramic Plunger Repair Kit 18mm for Annovi Reverberi RK, RKA, RKV, XRCA, XRV, XRCV Pumps AR2546 18mm Piston Kit Ceramic Plunger Repair Kit Fits for Annovi Reverberi RK RKA RKV XRCA XRV XRCV Pressure Washer Pumpsw AR2546 (18PCS) APPLICATION: Designed for use in the repair and maintenance of your existing RK, RKA, RKV, XRCA, XRV, or XRCV series pressure washer pumps.(also known as AR pumps). Package Included: 3 *Brass Slingers 3 * Ceramic Pistons 3 *Backup Rings 3 *O-Rings 3 *Copper Washers 3 *Piston Nuts