Covers the grill where air blow out and deflects air by 90 degrees, reducing noise by 10% to 15%. This non-electrical unit is quickly and easily installed on the air discharge with Velcro® for all units. Compatible with Velocity (X1, X2, and X4), CollectAll, DFH, SPU, JR, and PGR models and all Quatro Ductless fume hoods.