The 18 ml, round shape glass jar with Screw Neck are used fpr packing pain balm. These glass jars are 100% food grade certifed, FSSC 22,000 certified, flint (clear), 100% toxic free and lead free, microwave and dishwasher safe, and easy to wash and clean. These glass jars are chemicaly inert and unreactive and avoids leacing of chemcials into the packed product.