Technological Transfer Laboratory Model 125 Electrometer
This is an altered Model 5 CD V-710 ion chamber manufactured by the Victoreen Instrument Company. The civil defense sticker that should be on the side of the case is missing, and the original manufacturer's information on the top of the case has been covered by a sticker identifying this as an "Electrometer D.C. Amplifier Model 125." The company name on the sticker is the Technological Transfer Laboratory of Wausau Wisconsin—unfortunately I have been unable to locate any information about them. In 1974, Herbach and Rademan, Inc. of Philadelphia was selling these units for $12.95 each.
Detector: Plastic lined steel ion chamber
Range: 0-0.5, 0-5.0, 0-50 R/h
Batteries: Two 1.5-volt D cell and one 22.5 volt
Size: ca. 4 1/2" x 8 1/2" x 3 1/2" (excluding handle)
Weight: ca. 2 pounds