The Dock Shelter is used with doors up to 10'W x 10'H. The dock shelter reduces oversized doors to match truck openings. The long wear fabric is highly resistant to abrasion and tearing. Fiberglass staves are sewn into the flaps. Seal is formed along the sides and top of trailer when the vertical and top panels are pushed inward by the trailer. Recommend minimum 10" trailer penetration for a good seal. Supporting structure is made of 2" x 4" wolmanized lumber. The top header piece measures 132"W and contains a drop curtain which measures 36"H. Two vertical pieces measure 126" tall with vertical flaps measuring 21"W. When installed, the shelter will close the door opening down to 90"W x 90"H (between flaps). Includes two yellow steel guide protectors and foam-filled corner draft protector pads for extra sealing action. Units are non-returnable.