The water line on a dental unit fits through a rubber tube that is lined with insulation to maintain the temperature of the water If the water line has an outside diameter of 0 1875 inches in how thick is the layer of insulation Hint Remember that the insulation is on both sides RUBBER TUBE INSULATION WATER LINE 0 1875 IN INSIDE DIAMETER 1 4 IN I OUTSIDE DIAMETER 3 4 IN