This is a piston ring set of 3 for an Associated or United hit miss gas engine. They are 3 3/4" diameter and 1/4" wide and will work for any engine with a 3 3/4" bore and 1/4" grooves on the piston. They are new and have never been used. The pictures tell the story. I can be reached at 262 573 193 1 if you'd like to talk about them. Good Luck.