ACCEL's "Shorty" spark plugs keep your spark plug boots from being burned and your headers from being dented if you don't have enough room between your plug boots and your exhaust manifold or headers. Designed for trouble-free installation and removal in cramped spaces, these high-performance plugs are much easier than OE plugs to get a socket on but still deliver a larger, hotter, fuller flash front and significantly more power at high rpm. You'll have instant throttle response and better fuel economy with less fouling, flame dissipation, and misfire. These copper-core plugs provide increased thermal conductivity, come with machine-rolled 14mm threads to protect your heads, use a standard 5/8 socket, and come in a pack of four. Accels race proven U-Groove "Shorty" spark plugs are the cure for your "burnt plug boot" blues. The overall length has been reduced 1/4" to 3/8" to gain critical air gap space between the spark plug boot and the exhaust header tube. This helps eliminate burning the spark plug boot or dimpling the header tube. The shorter spark plug length also can make it easier to install and remove the spark plugs in certain applications where there is not a lot of room to fit a socket or move a wrench around.