This is the JConcepts 12mm Front Clamping Hex Adapter for the Associated B4.1. FEATURES: Converts the front of the Associated B4.1 to a clamping 12mm hex adapter Precision machined blue anodized aluminum INCLUDES: Two 12mm Front Clamping Hex Adapters with Set Screws REQUIRES: Team Associated 12mm hex conversion steering blocks and axles JConcepts Inverse wheels #3337 (white) or yellow (3337Y) or Mono wheels in White JCOC3344 or Yellow JCOC3371 for proper mounting, offset and handling characteristics COMMENTS: Compatible with JConcepts 12mm hex and Kyosho RB5 front wheels jxs 02/21/12 ir/jxs