Serological pipettes are manufactured from specially selected, heavy wall machine drawn borosilicate accurate bore glass tubing. They have precision fored jets and bevel ground ends to resist chipping. The graduation marks are in durable white enamel or amber stain; both are resistant to normal laboratory agents and repeated washing. All of the pipettes are individually measured and then marked. Accuracy is ensured between any two readings because of uniformity of the bore. The pipettes can be autoclaved and if necessary can be flamed for sterilization. Accuracy per Class "B".