This listing is for Radio Design Labs RDL ST-DA3 Stick-On Audio Distribution Amplifiers. There are multiple units available for purchase. They were all pulled from a working environment, power tested, and power on as they should. They require a 24V 500mA AC adapter, 1 will be included with each unit purchased. There are light signs of wear on all available units from previous use. All photos are of the item(s) that you will receive. We do not provide tech support for these devices. If you have any questions, feel free to contact me.