Super Stay Alive is the natural partner for your Zen Decoders, however they are also ideal for adding to high quality sound decoders which allow stay alive installation such as ESU, Zimo and others Despite their excellent power storage ability, the Super Stay Alive is very good value and slightly smaller than competitive products. Installation is easy Just match the blue and black wires to the blue and black stay-alive wires already attached to your Zen decoder. The overall size of Super Stay-Alives is a compact 32.3mm long x 16.1mm wide x 5.3mm high