Aokin Tactical Rifle Bipod 6-9 Inches Adjustable Spring Return Sling Swivel Mount Aokin gun bipods for rifles is made of Premium Quality Hardened steel and aircraft aluminum alloy with black anodized finish,Compact,lightweight and portable With return springs and leg release button,there are 5 settings for different length required and can be adjusted from 6 inches (152mm)to 9 inches(225mm) Nonslip rubber on the bottom of the legs makes the bipod grips shockproof,antiskid and hold the rifle more stably and shoot more accurately Foldable arms with robust external spring tension control, can be easily assembled or disassembled in any battle field Quickly attaches rifel to or detach it from sling swivel stud, pivot model allows shooter to compensate for ground that is unlevel by up to 20 degrees