This is a set of optional RPM Rear A-Arms, and are intended for use with the Traxxas Electric Rustler and Stampede trucks. RPM rear A-arms for the electric versions of the Traxxas Rustler & Stampede are stronger and more durable than stock versions, but each arm is also 7 grams lighter than the stock parts! That’s 14 grams of unsprung weight eliminated with a single pair of rear A-arms! Coupled with a set of RPM front A-arms, the total weight loss exceeds 24 grams or almost a full ounce! RPM accomplished this without creating any weak points nor are our A-arms any more flexible than the stock versions. Additionally, RPM has adjusted the shock mount locations slightly to allow more noticeable tuning adjustments when using the inner or outer shock mount holes (while the center hole remains in its stock location). RPM also eliminated over 0.030” or 1/32” of slop from the inner arm mount and more than 0.010” or slightly less than 1/64” of slop at the outer hinge pin for an ultra-smooth, slop-free suspension system.