Ultimate Arms Gear Heavy Duty 9" - 12" Tactical Low Profile Folding & Height Adjustable Aluminum Bipod For Weaver Picatinny Rail Side Mounting System High Tech Durable Machined Aluminum Military Quality Construction With Non Slip Rubber Feet Simple Spring Operated Leg Extender : Extends From 9" - 12" Critical Posi-Lock Feature To Prevent Tipping Folds When Not In Use And Locks In Folded Or Unfolded Position Side Mount Attaches To Any 7/8" Weaver-Picatinny Rail: Perfect For Handguards, Rifles, Airguns, Paintball, Airsoft With A Weaver-Picatinny Rail