The random interval generator v.3.x. creates either random or fixed intervals that are terminated by audible beeps. The beep is a 700hz tone that is delivered through a switchable onboard speaker or an external earphone, both controlled by a volume control. Random-interval or fixed-interval mode is selected by a switch inside the case. The interval lengths are easily programmable by switches inside the case from a mean length of 5 minutes to a mean length of 4 hours. If the device is left unattended, it enters a battery-saving "chirp" mode. Dimensions (inches): 4.15 X .85 X 2.40. Weight including batteries: 4.5 oz. The photos are actual size.
Operating instructions.