Selectively target sound at listeners to prevent sound from bouncing off of reflective surfaces for a richer, clearer sound. Each 30-watt speaker connects easily to projectors and TVs and includes fixed and variable volume outputs to connect additional speakers or even a dedicated assistive listening system. Both models operate on 115V AC power and include brackets for mounting on whiteboards. Each features two 1/4" microphone jacks, two audio line-in RCA jacks, fixed and variable audio line out RCA jacks, volume control, tone control and mounting hardware. Choose Model PI30-PS for wired audio connections. Each speaker measures 12"H x 5"W x 4"D. Six-year warranty.