The sunglass counterpart to the RX3946V, the RB3946 Clubmaster Oval also takes a 145mm acetate temple matched to its rounded front. A compatible replacement needs to hold that same oval curve, since the Clubmaster Oval sits apart from the squarer Clubmaster styles that share a similar name.

Replacing a cracked or worn acetate arm costs a fraction of a new frame, which matters here since the acetate front on Clubmaster-style models is usually the more involved part to remake. A matched aftermarket arm gets the RB3946 back in service without touching the part that's still fine. It's the more practical route whenever the front and lenses have held up better than the temples. Comparing the arm against the front in natural light is the simplest way to judge whether a shade difference is really a mismatch.