Adapter ring to attach ML-3, MR-14EX, or MT-24EX to most lenses with 52mm filter size.

Not recommended for use with the EF 28-80mm f3.5-5.6, 28-70mm f3.5-4.5, 35-70mm f3.5-4.5 or FD 28-55mm f3.5-4.5, 35-70mm f3.5-4.5.
Already built into the ED 50mm f2.8 Macro, 100mm f2.8, 100mm f2.8 USM Macro and MP-E 65mm.