This product is great for measuring out your products that require dilution. This model is designed for use in gallon containers. To install the Proportion aid, simply place the tube inside the gallon and screw the device on like a cap. To use the Portion Aid, squeeze the gallon until the Porportion cup is filled to the desired amount. Then you may pour the contents of the Porportion Aid into the secondary container. Use with cleaners, disinfectants, detergents or concentrates. Ounce and cc calibrations molded-in on sides; both are 3 oz. cups. Eliminates extra cost of proportioning bottles.