The 9 Volt Single Level Sensor is an aid for people with vision impairment to fill cups and glasses with one level of liquid.
	
	
	
The unit simply hangs over the side of a cup or glass with the metal prongs on the inside of the container.
	
	
	
Produces a loud buzzing 400Hz tone with slight vibration.
	
	
	
A standard 9 Volt Battery plugs into the base for easy battery change.
	
	
	
Comes with battery already inserted ready to use.