Check the listing for details. Automatic Technology 87618 Mini Door Extension Kit for Rolling Steel or Roll Up. Condition: New. Listed at 109.95 USD. Automatic Technology 87618 Mini Door Extension Kit for Rolling Steel or Roll Up Extends the length of a rolling steel or commercial roll up doors’ axle to accept a Dominator ShedMaster Sheet Door Operator. The axle extension kit adds approximately 4-1/2 inches of room to either side of the door so an automatic sheet door operator can be properly installed. Each extension kit includes two pieces of extension pipe, hanger bracket, U bolt and saddle, self tapping screws, nuts, bolts, and installation instructions. The kit is designed to fit on 1-inch and 1-1/4-inch rolling steel door axles and has a straightforward installation for both configurations. What is included: Hanger BracketExtension Pipe 1” ODExtension Pipe 1-1/4“U Bolt and SaddleHex Head Self Tapping Screws (4)Nuts and Bolts (2)Features: For rolling steel doors, commercial roll up doors, corrugated doors, and other metal sheet style mini warehouse doorsIncludes all garage door hardware required to extend the door axleAdds approximately 4-1/2-inches of space on either side of the door so a sheet door operator can be installedFor door axles 1-inch and 1-1/4-inches in diameter