DATA LINE PROTECTION: Prevents power surges that travel through telephone lines from causing damage to electronics. AUTOMATIC VOLTAGE REGULATION (AVR): Corrects minor power fluctuations without switching to battery power, thereby extending the life of the battery.A compact UPS with line interactive topology, the AVRG750U provides battery backup (using simulated sine wave output) and surge protection for desktop computers, workstations, networking devices, and home entertainment systems. The AVRG750U uses Automatic Voltage Regulation (AVR) to correct minor power fluctuations without switching to battery power, which extends battery life. AVR is essential in areas where power fluctuations occur frequently. Any product you return must be in the same condition you received it and in the original packaging. We usually respond within 24 hours on weekdays. Thank you for shopping at our store.