Sears Tower Model 6156 GM Meter (ca. 1955-1960)

Sears Tower Model 6156 GM Meter (ca. 1955-1960)

This GM survey meter was manufactured for the Sears Roebuck Company by El-Tronics Inc. of Philadelphia. A very similar instrument was sold under the El-Tronics name as the Model PR-4. The latter was described in the Atomic Energy Commission Instrument Catalog as follows: "Light weight field geiger survey meter for location of radioactive ores; provides visual and audible indication of radioactivity by flashing neon light and loud clicks in phones."

Sears Tower Model 6156 GM Meter (ca. 1955-1960)

The photo shows the original box that the instrument came in.

The GM tube is mounted inside the case at the bottom. It is covered by a thin mylar (?) window.

Detector: GM tube, 30 mg/cm2 wall

Size: ca. 4" x 7" x 1 3/4"

Weight: ca. 3 lbs.

Output: No speaker, but it has a phone jack and a small light that flashes according to the count rate

Batteries: Two 1 1/2 volt


  • Sears Roebuck & Co. Instructions for Geiger Counter Model 6156. No date.
  • Atomic Energy Commission. (El-Tronics PR-4), AEC Radiation Measuring Instruments, RIB-8 (supplement 2) July 1, 1954, page SGM-110A.