The California Sunbounce Sun Strip Mini Crossbars can transform the 3x4' mini frame (sold separately) to make it compatible with a narrow (8x36") Sun-Strip reflector screen (optional).The California Sunbounce System has different sized aluminum frames that can be attached with light-reflecting, light-reducing, or light-absorbing screens to handle different lighting situations The sun strip reflector used with these crossbars help prevent light spill and enables quick light fall off