Ade Advanced Optics Hunter's 9"-15" Heavy Duty Long Bipod + Free Picatinny Rail Adapter, 9-13 Quality manufactured with cold forged hardened steel and 7075 T7 alloys. These bipods are the heavy duty version with thicker stronger reinforced legs, Heavy Gauge Steel Full Cradle, Heavy Duty Springs. It can handle the heaviest magnum recoil. the spring legs can be adjusted and you can pulling the leg from 9" to 15" Hinged bases have tension adjustment to eliminate tremor. Bipods have an all-weather black heavy duty anodized finish. Very Light Weighs 13-Ounces Attaches to sling swivel stud and comes with WEAVER/PICITINNY RAIL ADAPTER.