Tests for RF interference on MegaCode and AllStar based access control panels, receivers, and garage door operators. Compact and lightweight with battery save feature. Built-in speaker lets user hear what receiver hears. Special tone simplifies transmitter testing. Visual LED indication to confirm interference. 318MHz center frequency. Power: 9-volt battery. Dimensions: 2.5 in. W x 5.75 in. H x 1.25 in. D