These are spare suspension arm parts for the TRF420 racing chassis kit. - TRF420 D Parts x2 - Components are molded in carbon fiber-reinforced plastic for superior rigidity. - The tweaked design uses aluminum inserts for damper attachment. Using different inserts (sold separately) allows adjustment of lever ratio, with three different setups possible. - Rear arms are 3mm offset to the rear, allowing the shorter TRF420 lower deck (while keeping the same wheelbase) and giving increased rear traction. - For use with 3mm diameter shafts (sold in Item 51637). - Compatible with TRF420, TRF419*, TA07* and TB-05 PRO* chassis cars. - Note: *Rear arms have different offset to kit standard parts, and require adjustment of wheelbase using spacers, etc.