Specifications:

Input voltage: 120 v AC, 60 Hz

Output voltage: 16 v AC at 30 VA

Dimension : 3.9 x 2.6 x 2.4 inch/ 10 x 6.5 x 6 cm (LWH)

Note:

This product is not a Ring doorbell product, the brand mentioned above is only for demonstrating compatibility.

Universal Compatibility: This 24V transformer is compatible with Nest, Honeywell, Sensi, Ecobee smart thermostats; smart doorbells (Ring series, Nest Skybell, etc), zone controlled HVAC systems, surveillance cameras, or any other device requiring 24V AC power; Note: the brand names above is only for demonstrating compatibility.
POWER UP MULTIPLE THERMOSTATS / DOORBELLS: replaces and upgrades underpowered transformer with this 24V AC transformer, offering plenty of power for single or multiple thermostats and doorbells at the same time.
PRO UL Listed: Aerb ring doorbell transformer is UL/CSA listed; Built-in thermal cut-off switch offers an extra layer of safety, shutting off power in the event of excessive temperature. Input - 120 V/ AC, 60Hz. Output - 24V,40VA.
One for All: Your old transformer didn’t work out with your modern smart video doorbells or thermostats? We’ve found you the solution. This Aerb transformer is for powering up your devices with stable power for your devices to avoid lack of power, connection issues, low-quality video resolution, and low chime volume.
Service and Support: All products come back by a 30-day change period,1 Year maintenance period.