Cold Steel SRK (SK-5), Fixed Blade Knife, SK-5 with Black Tuff-Ex Finish, Plain Edge, 6 Blade CS-49LCK Survival & Rescue operations demand a versatile knife able to withstand the most extreme conditions. Simply put" the Cold Steel SRK (Survival Rescue Knife) was designed specifically with this in mind. A popular knife with Military and Tactical Law Enforcement Personnel" the SRK is the standard issue knife of the Navy SEALS for their BUDS - or Basic Underwater Demolition training - the SRK has proved its worth time and time again in the most demanding environments.