Seal XR Folding Knife 3.9in S35VN Blade Straight Black Glass-Reinforced Nylon Handle Grey/Black. The SEAL XR provides the feel and functionality of a SEAL knife in the form of a large format pocket knife. Built from GRN and S35VN steel the SEAL XR is an extremely durable knife with high corrosion resistance and edge retention. Fully ambidextrous design the SEAL XR locks open with the secure XR lock. One of the best tactical knives available today.