Lock-it Socket Set (2) Set includes 5/8 and 13/16. Extended Length Lockit Socket® Spark Plug Socket - Patented spring clip design. No more broken insulators. No rubber inserts to wear out, stick and slip. Snug grip-easy release. Slim profile for tight spots. Gnarly knurl for great grip. Overall length: 3-1/4 inch. Extended length sockets were designed at the request of techs who wanted a tool to protrude beyond heat shields, and which could be used with a ratcheting wrench. Proven socket design utilizes a patented spring clip method to grip spark plugs firmly and release easily. This spark plug socket has a lifetime unconditionally guarantee against any defects or breakage. While damage to the replaceable spring clip is very rare, a spare spring clip is included with the purchase of each tool, just in case.