Williams Sound BKT 024 Omindirectional Wall Ceiling Mounting Bracket Omindirectional wall or ceiling mounting bracket. Use with a single TX9 or TX90 transmitter, WIR TX75 transmitter and WIR TX75-S emitter Technical Specs Base 1 2¡± (50.8 mm) round base with four 0.188¡± (4.8mm) holes on 1.6¡± (40.6mm) bolt circle for solid surface mounting Base 2 T-Bar Clip for drop ceiling rails Base Cover Black Vinyl, covers either base Shafts Two 0.5¡± (12.7mm) diameter, 2¡± (50.8mm long aluminum, black. 1/4-20 stud with lock ring. Head 190¡Æ Tilt, 360¡Æ Turn & 360¡Æ Rotation Finished Lengths 2¡±, 4¡± or 6¡± Maximum Weight 3 lbs (1.36 kg) Shipping Weight 0.3 lbs (166.5g) Compatibla with WIR TX75 - Mid-range Infrared Transmitter WIR TX75-S - Slave emitter for TX75 WIR TX9 - SoundPlus¢ç 2-channel Infrared Emitter WIR TX90 - SoundPlus¢ç 2-channel Infrared Transmitter