RPM front A-arms for the Electric versions of the Traxxas , Rustler & Stampede are sold in pairs and are available in black, green, blue and red. These A-arms are molded with what is fast becoming an RPM trademark design of angled leading and trailing edges to reduce frontal edge mass and improve the a-arm's ability to ride up and over tall obstacles instead of slamming into them. RPM A-arms are extremely rigid for a superior ride and stability over the roughest tracks and terrain.