3-button transmitter contains 2 command buttons (typically foward and back) plus 3rd button controlling a bright green laser diode.
Model PC-AS3 contains two sets of batteries: 2 CR2032 (20 mm) coin cells for the transmitter and a separate high amp-hour battery (CR123) for the laser. This assures virtually unlimited life of the transmitter and up to 25 hours for the laser.