Plain Edge, Kershaw Ken Onion Whirlwind Zytel® handle Torsion Assisted Opener. The Polyamide Handle Whirlwind With a 440A stainless steel blade and Featuring the "Speed-Safe" torsion assisted opening system designed by custom knife maker Ken Onion. The blade is 440A stainless steel with a hardness of 55-57. The Polyamide handle (similar to Zytel®) provides a very strong and solid grip and the stainless liners add rugged durability. Blade Length: 3-3/8" (8.6cm)", Length Closed: 4-3/8 (11.1cm)", Weight 4 ounces.