Calibrated to contain. Pipets are 5 inches long with a single black capacity ring and are color-coded for selection of the correct size. Clean and ready to use. Made of soda lime glass in compliance with ASTM Specification E438, Type II glass requirements. Filling is easy. Capillary action draws the fluid into the tube. To dispense, simply cover the hole on the rubber bulb and squeeze. Packaged in easy-open cylinders for convenient dispensing. Each cylinder contains 250 pipets and one pipet device. Designed from ASTM Specification E672 requirements.