The ANTOP AT-601B (Black) Smartpass Amplifier features a Smart Switch to balance the amplification between short and long range signals received by the antenna. Dual-color indicator, Green for long reception and Yellow for short reception. Includes a built-in 4G Filter to block 3G and 4G wireless signals to ensure noise-free digital TV reception. High gain is designed to amplify VHF and UHF signals with a low noise level, less than 2dB.