Gratnells Extra Deep Tray of 15 Voltmeters with Lid. Digital Satz Voltmeter High quality School bench voltmeter. Range: 0-20V. Resolution: 0.01V. Super strong high grade ABS case. Protective display window. Large bold 14mm LCD display. Screw locking battery compartment. Colour coded & shrouded 4mm sockets. Power: 1 x 9v PP3 battery, inc. Dims: 95 x 90 x 75mm. 12 month guarantee.