This works with the Now TV 4200SK ("by Roku"), which states 5.99V on its bottom. Not sure what else it is compatible with. On my expensive Panasonic TV this only worked with 1 out of 3 USB ports. Dunno why! On my two cheaper TVs (a Samsung and a Toshiba) it worked in all USB ports. Now when the TV powers on the Now TV automatically powers on too, which is fantastic. Only concern is the USB end is quite fat and it nearly did not fit into the USB port on the Toshiba (which is what I need it for) due to Toshiba only allowing enough space in their design for a regular USB cable. But after applying some very careful brute force it finally squeezed in. At least I know it will not fall out! This adapter works as described and is a brilliant solution to the regular 3 pin power socket problem I needed to solve. Dropped 1 star due to fat USB and due to it coming in 2 parts - the adapter for the adapter so it fits the Now TV DC socket size.