These Oxo-Biodegradable Flexy-Glass Pint To Brim Tumblers CE Marked are thin walled polypropylene tumblers that are crack resistant.. The tumblers are designed with a step in the base, for maximum stackability. This also allows them to be easily pulled apart, thus making them ideal choice for outdoor events like festivals, in clubs, beer gardens, busy bars and areas where safety and speed of service are of primary importance. Manufactured under strict hygienic conditions the tumblers are sleeved to keep them clean and dust free.