The two attaching bolts put tension on a coat hanger type wire retainer that rests at the bottom of the barndoors main body. THe wire can be hooked and un-hooked into a retaining notch. A simple,yet fast-removing system that allows you to set the tightening bolts for reflectors from 6.5 inches to 7.5 inches,which would include "many" monolights with their standard reflector. This is a Speedotron Brown Line M11 convection-cooled light head, which has the "standard" 7 inch Speedotron universal mount grid reflector bayonetted into place. Onto the 7 inch reflector is where the barndoors unit is mounted.