PZT CB-27, made by Państwowe Zakłady Tele i Radiotechniczne, State company for tele & radio technique in Warsaw.
27 stands for the year of its introduction, 1927.
Metal box telephone. The metal housing contains all electrical components with the dial on a separate bracket, attached to the stem of the hookswitch assembly. The construction and design are very similar to the BTMC 2652.
The mechanism of the dial is a Polish version of an Ericsson dial.