Register Boot with Ceiling Diffuser combinations are even easier to install, wont dent or rust and are paintable or with Custom Graphics including wood grain, stone, camo and other designs. The ceiling boots are 8, 6 in. and an 8-7-6 in. reducing model. The diffusers comes in Round Capital Crown molding models.Features. Color - White.. Shape - Round.. Ceiling Diffuser.. 8 in. Boot with Butterfly Damper.