Ade Advanced Optics Hunter's 13"-23" Heavy Duty Long Bipod + Free Picatinny Rail Adaptor 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 13" to23" Hinged bases have tension adjustment to eliminate tremor. Bipods have an all-weather black heavy duty anodized finish. Attaches to sling swivel stud and comes with WEAVER/PICITINNY RAIL ADAPTER. Very Light Weighs 14.1-Ounces