Warehouse Dock Door Seals are designed with an auto push back head curtain adjusted automatically as the truck backs into the dock lowering energy costs by sealing out weather elements.This unit provides seals for 9' wide x 10' tall door openings. The 10" projection seals are to be used with a 4" to 6" dock bumper projection. The 20" projection seals are to be used with Edge of Dock Levelers inclusive with a 14" to 15" dock bumper projection.