LUDLUM provide different variation of the pock-sized survey meters of the Model 2401 Series that is targeted for very specific types of radiation detection (i.e. gamma, alpha, beta, x-ray, etc)
Most of the Model 2401 Series are 3-Range Analog Meters, with the only exception of Model 2403.
Model 2401 Series

Model 2401-EC
Gamma Survey Internal Energy-Compensated GM Detector Sensitivity (137Cs): 1050 cpm per mR/hr

Model 2401-ECA
Model 2401-EC with alarm

Model 2041-EC2
Model 2401-EX with a Sensitivity (137Cs) of 100 cpm per mR/hr

Model 2041-EC2A
Model 2041-EC2 with alarm

Model 2401-EW
Alpha-Beta-Gamma Survey Integrated Meter with End-Window GM Detector Sensitivity (137Cs): 1050 cpm per mR/hr

Model 2041-EWA
Model 2041-EW with alarm

Model 2401-P
Alpha-Beta-Gamma Survey nternal Pancake GM Detector Sensitivity (137Cs): 3300 cpm per mR/hr

Model 2401-P Dose
Model 2401-P with Dose Filter

Model 2401-S
microR Pocket-Size Survey Meter Low-Level Gamma & X-Ray Survey Internal CsI Scintillator Detector Sensitivity (137Cs): 100 cpm per µR/hr

Model 2402
Pocket-Size Ratemeter with alarm Accommodates a Variety of Detectors

Model 2403
Model 2402 with 4-Range Analog Meter