Ion chamber w/air at atmospheric pressure.  Includes the build-up cap.

High range gamma monitoring applications with 1mR/hr to 20,000 R/hr range

Can be used with extension poles or with extended cables for underwater surveys

Chamber active volume: 50cc

Probes are sold separately with the following ranges:

RO-7-LD (Low Range Detector) up to 1.999 R/hr with 0.001 R/hr resolution

RO-7-BH (High Range Detector) up to 19.99 KR/hr with 10 R/hr resolution