Cadrim Decibel Meter - Digital Sound Level Meter, Self-Calibration Decibel Reader, Noise Meter with LCD Display Measurement Range 40-130 dB spl Meter (Battery Included)…: Amazon.com: Industrial & Scientific
Transistor Radio Battery - 9 Volt 20-604 - NEDA 1604 Power-S Midland
9-volt, E battery, PP3, 6LR61, 6F22, 1604A, 1604D, MN1604 Battery Equivalents and Replacements