This is the standard audio handset for most audio door entry kits by BPT. It is commonly used with vandal resistant and Targha range entrance panels. It's an extremely popular handset as it comes with a high build quality and is reasonably priced.
This audio unit from BPT comes complete with a loudspeaker and a microphone, both with adjustable volume level controls, making it a very useful module.
This entrance relay unit is designed to allow the residence to communicate and control the opening of multiple entrances.