15" radius torsion hardware; track is 2" hemmed and bracket mounted. 3" track supplied when required by weight. Heavy duty steel rollers, non corrosive door fixtures and 14 gauge graduated hinges are standard. Double end hinges and long stem rollers are included on doors 16'-2" wide or as required by weight. U-shaped galvanized struts are supplied on doors over 14'-2" wide or as required by weight to keep the door rigid. All doors are standard with interior slide bolt lock.