This is an amplifier that amplifies signals in the terrestrial digital and CATV frequency bands. The power supply unit is removable, allowing for power to be drawn from inside the house. It was working well before removal. Please note that we cannot guarantee the operation of this used item. We have multiple used items of similar condition, so bulk sales are also possible. If you are purchasing multiple items, we will create a dedicated listing with a discount, so please consult with us in the comments. [Product Description] CATV upstream (10-60MHz), downstream (70-1000MHz) The upstream band can be selected for amplification or cut (for interference noise countermeasures) via a switch. Gain: Upstream 15dB～20dB, Downstream 25dB～30dB