Not all transformers are equal. NuTone transformers feature an easy-to-install lock-mount or wall-mount that can reduce installation time by 25%. An additional unique feature is the thermal cut-off switch designed to shut off the door chime system in the event of excessive temperature. NuTone saves you time and money. 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. 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.