20 tooth compound gear with 10 tooth pinion. Fits the 1/8 inch round axles sold elsewhere on this site. 1/8" inch pitch. 0.457 inner gear diameter. 0.855 outer gear diameter. 1 Each Compound (20T/10T) MASGR10$0.89 Copyright © 2003-2009 E-Clec-Tech. All rights reserved. All other materials and logos are copyrighted by their respective owners, or companies.