Check out any of the seventeen Front Arm components enlisted.
The most reasonably priced component used on the Trx500fma 2010 (a) Australia Front Arm is the Pin Cotter 3.0mm.
A sample from the products for the Front Arm include: Arm Assy R,fr Low, Bolt,flange,6mm, Arm Assy R,upper, Pin Cotter 3.0mm.