NcStar Precision Grade Bipod Compact 3 Adapters Attach to any Sling Swivel Studded Firearm Aircraft Grade Aluminum and Steel Construction Spring Loaded Folding Action Attach to any sling swivel studded firearm Aircraft Grade aluminum and steel construction Compact Model with an Adjustable Height of 5.5-8 inches and spring loaded legs retract instantly with a push of a button Includes 3 Adaptors: AR-15 Hand Guard Sling Stud , Universal Barrel Mount, and Picatinny Rail Sling Stud