ADJ UBL9/12H, Linear Diffusion Filter accessory for the ADJ UBL9H and UBL12H linear fixtures. Changes the beam angle from 17-degrees to 1x40-degrees. Ιt ensures an even wash of light on walls, creating a stunningly uniform field, especially near the source. Easy to install, it effortlessly slides into the fixtures channel, secured by the included thumbscrew.