This is a Dynalite RR-AR Angle Reduction Ring It reduces the beam spread from select Dynalite heads from 140 to 60°. It may also be called a snoot. Use this item to highlight certain areas of your subject, or to keep light from scattering where you don't want it. Two can be combined for even greater reduction. It fits RH1050, MH2050, 1015, 2040 and 2050 flash heads.