Lil Red Barn Husqvarna, Stihl, Echo, Homelite, Efco Ring Compressor & Piston Stop Tool for Chainsaws Makes Piston and Cylinder Installation Easy!! Piston Ring Compression Kit For Chainsaws Stop locks pistons in 2-Cycle engines to help the removal of clutches & flywheels Useful for assembling pistons and cylinders on chainsaws. Works for Stihl, Husqvarna, Homelite chainsaws and many more! 4 different sizes of clamps for various sized chainsaw pistons.