This is the optional JConcepts Front Axle for 12mm Hex Conversion for the Team Associated B4.1. FEATURES: Steel construction Free spinning design eliminates C-clips, screws and other items INCLUDES: Two Front Axles Two 4-40 Mini Lock Nuts Two Thin Axle Shims Assembly Instructions REQUIRES: #9880 (ASCC9880) Steering Block Hex jxs 01/07/12 ir/jxs