NuTone C915 Junction Box Transformer for Door Chime 16-volt, 10VA transformer for use with most NuTone door chimes; order in standard package of six to help assist with your planning and still retain that economical edge Quick install transformers, built to last so you should have fewer call backs Fits in standard junction box  run one wire and the door chime is ready for use; installation convenience saves time allowing you to move on the next project quicker One 16-volt, 10VA transformer needed for a single chime cULus Listed for safety, ensuring you have a quality, reliable transformer that will pass inspection