The V20 allows for multiple users via Fingerprint, PIN, or RFID Card. All registrations require the Master PIN.
: There is typically a 0-1-2 switch inside the battery compartment to set the volume to Mute, Low, or High. gateman v20 manual
: Approximately 1.5 years based on 10 uses per day. The Definitive Guide to the Gateman V20 Manual: