Unit is self contained, no other equipment needed. 12 Volt, 4.5 amp/hour sealed lead acid battery included inside unit. LED indicates connection to battery circuit. Protected by a 4 amp circuit breaker. Direct wired OBD2 connector Saves all drivability codes and settings when disconnecting a vehicle's power (battery). Power on/ power off switch and includes 120V AC charger. Also protects settings for: anti-theft radio codes, clocks, keyless entry systems, alarms, cellular phone settings and other memory related functions.