Powerbuilt 648434 Wrinkle Band Piston Ring Compressor Made to be the most reliable tools in the market today Tool solutions for most all situations Built to exceed tool standards For compressing rings on pistons 2-Inch to 5-Inch in diameter Time saving low friction ring compressor uses a wrinkle band design to cut contact area with ring in half Prevents the tool from sliding into cylinder One adjustment of the knurled knob sets the tool to the correct size for the entire piston set Lifetime Warranty