IHPSV4.5HF | Horizontal Firestop | 3" Top and 1" Sides / Bottom Spacers | SV4.5" and 7.5" Concentric Vent | IHP570440203SKU:H2248-1Inventory ID:03611718Select Item:Price: $53.40Quantity: To help minimize water infiltration it is recommended that the Firestop/ Spacer (SV4.5HF) be installed on the exterior side of the wall. SV4.5HF venting component is used on some Astria, Superior, and Lennox gas burning direct vent fireplaces. Check your model's Installation Manual for listed Secure Vent Components. Reviews Choose your rating12345