RPM's X-Maxx A-arms are designed to be the strongest, lightest arms available. Starting with the upper A-arm, they used their 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 the proven 1:5 scale HPI Baja A-arms, so you know they're tough. RPM has also created a double support beam on the lower arms to spread impact energy over a larger area, meaning hard hits won't force you into the "walk of shame". They're also universal fit, which means they'll fit on any corner of your truck. No more worrying which arm fits where.RPM X-Maxx A-arms are molded in their trademark blend of incredibly tough, engineering grade nylons and made in the USA. RPM X-Maxx arms are backed by their industry-leading limited lifetime warranty against breakage for worry-free performance you can count on!Tech Notes: Each package comes with one upper and one lower A-arm. Four packages will be needed to complete one full vehicle.