TT Electronics Level VI UK Plugtop Switched Mode Power Supply Units – TT Electronics T6369ST, This 18V DC, 1.33A switched mode plugtop power supply from TT Electronics has standard UK 13A plug pins and a standard 5.5 x 2.1mm centre positive output connector. TT Electronics T6369ST 24W UK Plugtop PSU 2.1 C+ve 18V 1.33A