Amazon.com: I-Beam Heavy Bag Hanger; Steel Beam Clamp for Heavy Bag. Suitable for I-beams with Bottom Width 2.5" 6.3cm~7.5" 19cm; Can Withstand 450 Lbs of Gravity : Sports & Outdoors
I-Beam Clamp - Custom Size - Springboards And More
The American Gym: I-Beam Clamp, Gymnastics Hardware, JA-132