Decoder tester from ESU. Ideal to test decoders Before fitting. Not boxed. Selling as I have 2 See my other train items. AI Descrition. The ESU 51900 Decoder Tester is a high-quality digital control device designed for model railways and trains enthusiasts. Manufactured by ESU in Germany, this blue-coloured decoder tester is suitable for a variety of gauges and offers convenient control system functionality. Perfect for those looking to test and improve their digital control system, this model from ESU is a reliable tool for ensuring smooth and efficient operation in model railway layou
