RB3557 doesn't carry a shape nickname the way some Ray-Ban models do, but its spec is specific enough: a 145mm metal arm on a square front, which is what this aftermarket pair is cut to. At 145mm it sits between the 140mm arms used on several other square-metal Ray-Bans and the 150mm used on some acetate Wayfarer models, so it's not a length to guess at.

A square metal arm this length wears in the usual places — the hinge screw loosening first, then eventually the tip sleeve near the ear hardening or splitting. Neither issue affects the front frame, which is why a replacement arm, rather than a whole new pair of sunglasses, is the proportionate fix when only the temple has given out. Confirming the 145mm figure against the arm you're replacing takes a minute and rules out the two closest-looking alternatives in the range.

Frequently asked questions

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

A new 145mm arm includes its own hinge barrel, so if the wobble is coming from worn threading on the arm side of the 3557, replacing it usually restores a snug, tight fold.

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

Replacing both arms on the 3557 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 145mm hardware itself.

Can I replace just one arm, or do I have to buy both?

You can order a single side if only one arm on your 3557 is broken or scratched, or buy the pair if both need replacing — either way they match the 145mm length exactly.

Are these official Ray-Ban replacement parts?

These are compatible aftermarket arms, independently produced to match the 3557's hinge and 145mm length. They aren't manufactured or supplied by Ray-Ban, just built to the same measurements so they attach correctly.