Zak Model 15SW Handcuff Key Extension Tool with Swivel. The standard Smith & Wesson keys are thicker than other standard keys and won't fit in the regular Zak extension tool. This tool is specifically made to accommodate S&W keys. 3 3/8" long without key. "Enhances use of the original key due to the extended barrel length and keyring swivel feature. This allows the user to manipulate the key by rolling the barrel between the thumb and forefinger. To replace the key, unscrew the end cap and insert a new key. Replace the cap and its ready for use. Original issue key is not included in the lifetime guarantee. HANDCUFF KEYS NOT INCLUDED.