This instrument is a general purpose, digital ratemeter with a built-in scaler that provides timed counts over a user specified period. The instrument additionally includes an internally housed energy compensated GM tube with a range up to 10 R/hr. A front-panel switch allows the user to select between the internal GM detector and an external detector of choice connected via the cable. The LCD presents readings in a four-digit moving decimal format together with one of a wide range of available units of measure and is accompanied by several operational and alert icons. The LCD backlight can be activated and remains lit for a user-adjustable interval. This instrument features adjustable alert and alarm setpoints for both the Ratemeter and Scaler modes. Front-panel controls include a rotary switch for selecting between Off, Ratemeter Mode, and Scaler Mode; separate switches for audio on/off, fast/slow response time, and detector selection; plus push-buttons for activating the LCD backlight and for either resetting the counts or acknowledging alarms.