These are bicycle crank arm shorteners for reducing the pedal stroke for children or riders with shorter legs that can’t use regular length crank arms. This is a pair, both right hand and left hand sides. Fits 9/16-20 threaded pedals. Also great for people with limited mobility in one or both legs, or recovering from injuries and surgeries. Made from 6061-T6 aluminum with the highest quality alloy and stainless steel fasteners. 100% USA MADE. COMPARE ours to the competition. We have the Best USA made quality and price. If your crank comes 1/8” or closer to the chain, these will NOT work for your application. SEE PHOTO. NOT RECOMMEND FOR RIDERS OVER 190 Lbs. Please leave us positive feedback. If you have a issue, contact us first. We’ll do whatever we can to resolve it. Thank you!