The RB2448NM runs a square metal front on 145mm metal arms — 5mm longer than Ray-Ban's usual 140mm — and this aftermarket pair reproduces that extended length along with the straight-edged profile, so the hinge sits flush against the front the way the factory temple did. The 2448 family covers a couple of closely related codes, so ordering against the NM suffix specifically is what keeps the length and finish accurate rather than assuming any 2448 arm will do.

On a frame this size, the hinge screw carries slightly more leverage than it would on a smaller 140mm arm, simply because there's more metal swinging on it. It's worth a periodic check for play rather than waiting until the arm droops noticeably before tightening or replacing it. A 140mm substitute can look close enough to pass a glance, but it sits visibly shorter once actually fitted to this frame.