Amplivox SW227 Portable Wireless Powered Speaker Voice Projector Kit, Black No messy cables. Use inside or outside to reach audiences of up to 1,500 in rooms of up to 15,000 sq. ft. Includes lapel and headset mics with transmitter. Second dual module speaker has built-in 50W amp/receiver and 900 MHz transmitter. Can be placed up to 500 ft. away.