Ray-Ban's RB2140 Wayfarer runs a longer 150mm temple than most of its square-front siblings, finished in acetate rather than plastic or metal — both details this aftermarket pair follows. Getting the length right matters here specifically, since a 145mm arm, correct for other Wayfarer variants, will sit noticeably short on the 2140's frame.

Acetate arms are solid material rather than a hollow shell, so they don't crack the way plastic can — but they still rely on a small metal barrel set into the tip to carry the hinge screw, and that's the part that eventually works loose. Colour can also vary slightly between acetate batches, which is normal for the material and not a sign of a poor match. Where the barrel or the hinge itself is the problem, replacing the arm resolves it without touching the front.