Description These new style of silencers include acoustic foam, egg shell type of material fitted internally, designed for sound cancelling performance. Pre-fitted with 150mm flanges on either end. Both have similiar performance but vary in shape to accomodate the growers needs in grow tents and confined spaces. Choose from: 150mm GT Compact Acoustic 42.5(L) x 25.5cmØ 150mm Slimline Acoustic 54(L) x 22cmØ See pdf below for more images