Features: 1. 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). 2. REPLACEMENT ->> This 18mm piston kit contains Original Equipment AR replacement parts. Manufacturers Part #AR2546, Replaces part # 2757, Replaces Troybuilt Part # 193990GS. 3. Package Includes ->> 3 x AR1380940 18mm Ceramic Piston, 3 *Piston Nuts; 3 x AR962000 Copper Washers; 3 x AR1380950 Spacer;3 x AR600180 O-Ring; 3 x AR1080401 Backup Rings .(Total 18PCS, comes as shown in the first image). .