Exact item shown.
Sensitive Research Instrument Corporation Model ESD electrostatic voltmeter in the original wood carrying case, serial number 300462.
An exceptionally well-preserved example retaining its original factory standardization record, signed and dated January 18, 1952. The calibration certificate remains mounted in the case and documents the instrument's original 1% full-scale accuracy guarantee.
The original factory seal remains intact (see meter-face photographs; the seal is the black sealing wax applied to the access-cover screw at the upper right of the meter face). The calibration card states that opening the instrument or breaking the seal voids the original guarantee.
The instrument presents beautifully throughout. The wood case retains an attractive original finish, the leather carrying handle is clean and intact, the meter face is clean and legible, the glass is clear, and the original hardware is present. Photographs show the calibration record, factory seal, serial number, voltage terminals, case hardware, and overall condition.
Model ESD is a double-pivot electrostatic voltmeter intended for AC voltage measurement. The side panel provides 300, 600, and 1200 volt ranges through dedicated input terminals.
Sold as a vintage scientific instrument and collectible laboratory artifact. No electrical testing has been performed in order to preserve the instrument's original sealed condition.
Note to me: garage, right side rear, box G1