internal focus lenses only. Compatible with Master Prime Lenses, LWZ Alura, UP 14 mm, UP 180 mm, LDS-UP 14 mm and LDS-UP 180 mm; also compatible with wide-angle video lenses. Not compatible with external focus lenses. For use with MMB-1 top load. Can be used directly with R4 reduction rings, or used with R4 Ring: K2.65046.0 2x R4 Screw-In Reduction Ring 114 mm - 100 mm