50000ml 50L LabCradle Round Bottom Glass Boiling Flask by Simax  European made by one of the oldest scientific glass manufacturer from heavy duty thick Pyrex glass. You can select if you need more than one single neck. If you want necks at specific angle please add notes during checkout process. Also we can weld glass flanges and other parts to the flask as you desire. Flasks made in Europe are of higher standard and heavier by at least 50% of their Indian or Chinese counterparts