This extra sensitive GM-tube has a large window which makes the detector well suited for measuring low activity sources. This provides more counts and thus improves counting statistics for more accurate determinations of half-lives, etc. The GM-tube housing is supplied with a protective cover as well as a protective grid in front of the window. It is sensitive to alpha, beta and gamma radiation. It is complete with a removable protective cap, holder, and integral lead with BNC plug. This GM tube does NOT have built-in anode resistor, and therefore requires counter with built-in anode resistor. Suitable for use with Geiger Muller Counter - Frederiksen Code 80705. Useful diameter: 28.6 mm Recommended supply voltage: 500V BNC plug