Upper Arm Holder for A800FX FWD and A800MMX car.
AM19-FX-US provide exact same geometry as AM19-FX.
This new part is made from 3mm thick 7075 T6 high grade alloy, which mean it's 0,25mm thicker than AM19-FX.
To keep same rollcenters on toplinks like with AM19-FX its needed to run 0,25mm less shims under ST24 Ball Studs.
Info: Parts with "US" designation are especially designed for the use at tracks with hard boards/barriers.
During the different design compared to the standard parts, the "US" parts are more reliable at impacts.
Basically these optional parts are a bit more heavy than standard parts.