TRANSMITS AUDIO SIGNAL THROUGH WALLS, FLOORS, WINDOWS & CEILINGS AT DISTANCES OF MORE THAN 250 FT FROM TRANSMITTER; HIGH-QUALITY SOUND 2-WAY SPEAKER DESIGN; EASY & RELIABLE TUNING—PHASE-LOCKED LOOP CIRCUITRY GUARANTEES A CLEAR AUDIO SIGNAL; AUTOMATIC LEVEL CONTROL AVOIDS SUDDEN VOLUME BLASTS OR VALLEYS; DUAL POWER MODE RUNS ON OPTIONAL BATTERIES OR THE SUPPLIED AC ADAPTER; CHANNEL SELECT SWITCH ALLOWS USER TO OPTIMIZE RECEPTION