According to ARES, the spring-loaded U-joint built into the magnetic spark plug socket is unlike anything else on the market. This socket set allows the technician to easily install spark plugs on recessed and hard-to-reach applications.
Origin
The spring-loaded function in this set came from the difficulty related to installing spark plugs on many of today’s automobiles. Many spark plugs are recessed and require an extension and/or U-joint. A standard U-joint tends to fall to the side while these sockets allow for easier placement while securely holding the spark plugs in place with internal magnets.
Manufacturing/engineering specifications
Made from chrome vanadium steel (50BV30) with a high-polish finish. The hardness specification for sockets and U-joints is between 42 and 48 HRC. The set meets or exceeds ANSI standards and weighs 0.77 lbs in an EVA foam tray.