Metal temples at 140mm are what the RX6466's square frame calls for, and a compatible arm needs to hold that length precisely to sit right against the front. A shorter or longer aftermarket arm will still technically fit the hinge, but it changes how the glasses balance on the face.

A bent temple is the most common reason to replace arms on a squared metal frame like this one; the front usually stays straight and undamaged, so there's no need to replace more than the part that actually failed. Confirming the bend is in the arm and not the front hinge itself is worth doing before ordering a replacement, since the two problems look similar at a glance. Confirming the model number stamped on the inside of the temple is the simplest way to make sure a replacement will actually match.