The MP3298 Magnetic Pickup has a total length of 3 inches, threaded length of 3 inches, and thread size of 5/8-18 UNF. It replaces 20-01-0080 and MP100. The leadwire hookup measures 12 inches (305 mm). Magnetic Pickups supply RPM data to a tachometer when mounted at the flywheel ring-gear of an engine.