It consists of six built-in photocells and four digits digital counter to indicate the horizontal activity. It measures spontaneous and indicated activity. It also incorporates electric shocks of up to 100 V AC on 0.2mA indicated on a voltmeter for activating the animal. The counter is resettable. The stimulus is variable from 0 to 100 volts and is indicated on meter. Nicely finished, works on 220V/50Hz AC.