The Endevco® model 87 is a piezoelectric accelerometer with integral electronics, designed specifically for measuring ultra-low level, seismic events and low frequency vibration on structures and objects. The unit is hermetically sealed against environmental contamination, features a 1 V/g or 10 V/g sensitivity, state-of-the-art signal-to-noise ratio, and near-dc frequency response.

The model 87 incorporates an advanced ultra low noise hybrid circuit operating in a constant current mode. A simple two-wire system transmits its low-impedance voltage output and the required power. Signal ground is isolated from the outer case and mounting surface to prevent ground loops. A specially designed cable assembly is available as an optional accessory.