X-Maxx A-arms by RPM are designed to be the strongest, lightest arms available. Starting with the upper A-arm, RPM used proven A-arm designs from past successful builds to create an upper support structure sure to handle anything you can throw at it. The lower A-arm has better ground clearance than stock A-arms and has a cross section based off of our proven 1:5 scale HPI Baja A-arms. RPM also created a double support beam on the lower arms to spread impact energy over a larger area. RPM X-Maxx arms are backed by an industry-leading limited lifetime warranty against breakage.