Geiger-Müller tube holder, for use with GM tube (261-007) and scaler timer (EL10440). The unit consists of an aluminium box 58 x 33mm (Ø x depth) which houses the GM tube socket. Connection is through a 1m long coaxial connecting lead, terminated in a standard TNC connector (replacing the obsolete PET connector featured in previous units). A 2.2MW stabilising resistor is internally wired in series with the anode connection. 12 months warranty.