No need for a separate Transformer. This type of chime requires mains wired to the chime position then bell wire from the chime to the bell push Clear traditional "ding-dong" sound. This is a mechanical chime (not electronic) Cables not included. Please note this chime is not suitable for use with illuminated bell pushes Dimensions of chime: 170mm high x 112mm wide x 52mm deep, Manufacturer: Greenbrook