Automotive computer memory retaining tools designed to maintain the memory of the on-board vehicle computer (CCU) when the power source (battery) is disconnected. Use of these tools when changing or interrupting the power source prevents loss of certain drivability codes, keyless entry codes, digital radio setting, cellular phone settings and other memory related functions. Prevents loss of radio function on anti-theft radio systems. Use with 9 volt alkaline battery (not included)