The T-510R "universal" handset has been designed to replace a number of older model handsets from Golmar range and also from a number of different manufacturers.
 
Handset Compatability Chart.

The T-510R has an electronic and buzzer call tones.
It has internal speaker and microphone volume adjustment used when intitially setting up the installation.
 
Features:
The main characteristics of the T-500 series telephones with 4 n wires installations are:
Casing manufactured in polished ABS RAL9003 white colour
Detachable telephone cord with connectors
Wall mounting with multiple fixing points
Lock release button
Replaces the older style T-710R

 
Dimensions:
86mm x 229mm x 55mm