All Leatherman products are manufactured from 100% high-grade stainless steel. (Exception: Screw bits for the tool adapter are made of tool steel.) But stainless steel is not rust proof; it is corrosion resistant. Leatherman tool components are strong and the knives retain a sharp cutting edge..
Your Leatherman product should be cleaned, dried and re-oiled periodically to inhibit rust and corrosion. This is especially true if you use it in a damp or marine environment. After cleaning, re-oil pivoting areas with a light machine or penetrating type oil (such as WD-40). Buff stained surfaces with a polishing cloth or non-metallic abrasive (e.g., Scotchbrite pad or soft bristle brush).