The new Philip Harris GM Probe has been developed by our own in-house experts who sought to provide a more versatile and cost effective option for the general usage of a Geiger Muller tube in schools and colleges. Detects alpha beta and gamma radiation.The probe has a BNC connector and it does not require a separate holder meaning it can easily be mounted positioned and held using a retort stand and clamp.The probe is compatible with timers and counters that require an external anode resistor (including the Philip Harris S-Range Digicounter).Please Note: this GM Probe is not suitable as a replacement for the ZP1481 Tube used for the undertaking of the annual Radioactive Source Testing in schools. It is for classroom use only. Operating Voltage Range: 450 - 650VWindow Thickness: 1.5 - 2.0 mg cm-2Operating Temperature Range: -40 to +75°CAnode/Cathode Capacity: 3pF