This Profoto Glass Dome for the D1 and B1 Monolights lowers (warms) the color temperature of the light emitted by the D1 or B1 by 600K. It approximates the use of an 81B filter on a camera lens. Use it if the color temperature of the D1 or B1 is too blue for your preference or assignment requirements. The dome also diffuses the output of the flash while widening the beam spread. It snaps into place over the flashtube assembly.