Wireless Two to Two Doorbell Music / Ding dong Non-visual doorbell

Receiving Frequency:433; What's in the box:2Indoor Unit,2Outdoor Unit; Connection:Wireless; Kit Configuration:Two to Two Doorbell; Additional features:Non-visual doorbell; Answering mode:Ding dong,Music; Material:ABSPC; Listing Date:02/19/2019; Production mode:External procurement