Zipper, Gut Hook, Stainless Steel w/Rubber, Plain The Gut Hook's 420J2 stainless-steel construction delivers a high-quality cutting edge while the rubber-lined finger hole offers comfort during use. Rubber insert black finger hole handle. The 420J2 Stainless Steel blade is a mixture of carbon and chromium that has good corrosion resistance and easy machining qualities. Satin finish Plain edge blade.