Apex BASE uses a virtually indestructible hook knife constructed of poly carbonate plastic, it features a high quality stainless steel blade. It measures 4.1 inches in length. The hook knife is housed in a sheath that provides easy and quick access to the handle for extraction. The knife is secured to the pocket with Velcro. The pocket is secured by a “wrap around” design at the junction of the chest strap and the main lift web of the harness.