ECX Ring & Pinion Set: 1:10 4wd All Made by ECX; ECX is a United States based company; parts are sourced from China producers ECX Electrix part number 232022; UPC 605482116845 This item works with: ECX 1:10 4WD Circuit Stadium, 1:10 4WD Ruckus Monster, 1:10 4WD Torment Short Course