322, Zinc, Adjustable Door Guide, Designed For Single Sliding Or Bi-Parting Metal Or Wood Doors, Intended To Take Abuse From Trucks, Tractors & Farm Machinery When Used Around Factory & Farm Buildings, Smooth Ramp On Each Side Of The Guide Prevents Cutting Tractor Or Truck Tires, Mounts On Concrete Floors With Lag Screws & Shields Or On 6" x 6" Post, 1/2" Rod Or Bolt Inserted Through Hole In Each Side Will Serve As A Center Stop For Bi-Parting Doors, Meets ANSI/BHMA, 156.14 Manufactured From Hot Rolled Steel, Bulk.