Aladdin O-511KIT-9 Piston O-Ring Kit Replacement for 2-Inch Swimquip Plastic Backwash Slide Valve Piston O-ring kit replacement Fits pool and spa 2-inch Swim quip plastic backwash slide valve Includes 1 each O-130 index plate O-ring, 1 each O-245 valve cap O-ring, 2 each O-370 piston O-ring