Square frame geometry defines the RX6377, and its 140mm metal temple has to match that shape right at the hinge for the arms to close flush. A compatible replacement needs to be cut to this exact length, since even a couple of millimetres off is enough to leave a visible gap at the hinge.

Square frames like this one open to a wider angle than round styles, and that wider swing is what tends to wear the hinge screw down faster than the metal itself. A loose pivot, not a broken temple, is usually the reason to replace arms on the RX6377. Swapping in a compatible aftermarket arm restores the snug closing action without any work needed on the front. A quick look at the hinge area often reveals whether it's genuinely worn or just needs the screw snugged up before replacing anything.

Frequently asked questions

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 6377 is broken or scratched, or buy the pair if both need replacing — either way they match the 140mm length exactly.

Do I need a specific screwdriver to attach these myself?

You'll need a small eyeglass screwdriver, typically included in basic repair kits, to remove the old hinge screw and attach the new 140mm arm to your 6377 frame — the whole swap usually takes under five minutes.

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

Replacing both arms on the 6377 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 140mm hardware itself.

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

A new 140mm arm includes its own hinge barrel, so if the wobble is coming from worn threading on the arm side of the 6377, replacing it usually restores a snug, tight fold.