3 In. Thick Series 16 In. X 6 In. X 3 In. Hopper Vent for Glass Block Windows (A
Thick Series 16 In. Hopper Vent for Glass Block Windows (Actual 15.5 In. X 5.75 In. X 3.12 In.). The Clearly Secure 3 in. Thick Series Glass Block Hopper-style vent is designed to work with 3 in.