Specifications: input voltage: 120 V AC, 60 hz, output voltage: 16 V AC at 30 VA, dimensions: 3.9 x 2.6 x 2.4 inch universal powering for a single doorbell chime or up to three doorbell chimes, thermostatic and more devices in one home. Replace the old and under powered doorbell transformers for better performance. Compatible with Ring Pro and ring doorbells, WiFi and other smart thermostats like Nest and ecobee and more. Not compatible with ring chime pro. UL Certified to guarantee safety and quality.Safe and easy install I on. WARNING: This product may expose you to chemicals known to the State of California to cause cancer or reproductive harm. Accessory Type: Transformer. Color Family: Multi-Colored. Returnable: 90-Day. Voltage: 16 volt. Product Depth (in.): 2.6 in. Product Height (in.): 3 in. Product Width (in.): 2.6 in. Voltage: 16 volt