RX3857V is the optical Frank, built on the same 145mm metal arm as the RB3857 sunglasses, with the 'V' marking a prescription-ready front rather than a different hinge or length. This aftermarket pair matches that shared spec, so it fits either version of the Frank. Whichever version you own, the arm itself doesn't need to specify RX or RB — length and hinge position are the only two figures that matter for fit.

Frank's slim metal arms show wear first at the curve behind the ear, where the metal finish thins from daily contact with skin and hair — long before the hinge or the arm's overall shape gives out. That cosmetic wear is often what actually prompts people to replace an otherwise sound arm. If the hinge is tight and the arm isn't bent, a worn finish alone is a matter of preference, not a functional problem.

Frequently asked questions

Are these official Ray-Ban replacement parts?

These are compatible aftermarket arms, independently produced to match the 3857's hinge and 145mm length. They aren't manufactured or supplied by Ray-Ban, just built to the same measurements so they attach correctly.

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

Replacing both arms on the 3857 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.

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 145mm arm to your 3857 frame — the whole swap usually takes under five minutes.

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 3857, replacing it usually restores a snug, tight fold.