?16V 30VA Doorbell Transformer?Input: 120V, 60 HZ; Output: 16V at 30 VA; Low voltage hardwired doorbell power supply for residential, commercial and industrial use, offers reliable performance, safe to use ?UL Listed?This doorbell transformer has passed the ul test, which greatly improves safety and longevity, as transformer without this certification have a higher risk of circuit induced fire house problems during operation ?Compatibility?The transformer doorbell power supply compatible with Honeywell thermostat and doorbells, Nest, Ecobee, Sensi and Ring doorbell transformer ?Easy to Install?The 16V doorbell transformer is easy to replace and install, and can be screwed, threaded, or threaded clamped to the electrical box, and we provide clear wiring diagrams for proper wiring ?Professional Customer Service?Maxdot doorbell transformer focuses on high quality product and improving good customer service, if any doorbell transformer can't meet your expectation, please contact us and we will try our best to solve the problem; If the problem cannot be solved, you will be refunded or exchanged