RX5121 Wayfarer eyeglasses use the same longer 150mm acetate arm as Ray-Ban's sunglass Wayfarers in this size range, matched here for the square front's hinge position. This aftermarket pair is cut to that 150mm, acetate-arm spec rather than the shorter 145mm figure used on some other Wayfarer-family frames. Measuring the arm you're replacing takes a moment and avoids an easy mix-up between the two lengths.

The main wear point on an acetate Wayfarer arm is the embedded metal hinge barrel at the tip, which loosens gradually with use rather than failing all at once — you'll usually notice the temple starting to sit a bit looser before it stops holding altogether. Minor colour variation between a sun-faded arm and a new one is normal for acetate and not a sign of a mismatch. Replacing the arm resolves the loose hinge without needing to touch the front.

Frequently asked questions

Is it worth buying new arms instead of a whole new frame?

Replacing both arms on the 5121 costs from €26.95 with free worldwide shipping, far less than a new frame, and it's backed by a 3-year warranty against manufacturing defects on the 150mm hardware itself.

My hinge feels loose — will new arms fix that, or is it the frame that's worn?

A new 150mm arm includes its own hinge barrel, so if the wobble is coming from worn threading on the arm side of the 5121, replacing it usually restores a snug, tight fold.

What material are the arms made from, and will the color match my frame?

The arms are molded in an acetate or metal finish that matches the Square style of the 5121 closely, though very slight shade variation is possible since they're independently produced as separate aftermarket parts rather than cut from the same batch as the frame.

How do I know these arms will fit my Ray-Ban frame?

These arms are made specifically for the 5121, matching its 150mm length and Square hinge design, so they attach to your existing screws and hinge without any filing or adjustment needed.