Geiger-Muller Tube Holder, for use with Edulab Scaler Timer.  A 2.2M?stabilizing resistor is internally wired in series with the anode connection.

An aluminum box which houses the G.M. tube socket. Connection is through a 1m long co-axial connecting lead, terminated in a standard P.E.T. connector. 

Dimensions: 58 x 33mm (diameter x depth)