Time & Noise Meter
National School Products
HourGlass is a dual-function classroom management system that can be used as a Timer and as a Noise Detector. The giant display of lights is a dynamic measuring tool that can be seen by everyone in the classroom or even an auditorium. 15” x 8” x 4½”
Requires 4 “C” batteries (normally 6-months battery life) or optional AC adaptor.