Remote Entry Pro™ Tests Infrared (IR) and Radio Frequencies (RF) of Keyless Remote Entry Key Fob. Tests infrared (IR) & radio frequencies (RF) of keyless remote entry key fobs and other remote entry devices used by most vehicles. Can determine if the battery is dead or if the remote needs to be replaced. Can test at a distance to determine effective range. Attaches with magnetic backing to toolbox or vehicle. Automatic shut-off saves batteries.