2 oz bag. Five Star's PBW is the only patented, non-caustic cleaner developed for and used by professional brewers all over the world. Now you too can clean like the pros do! PBW is a non-hazardous, buffered alkaline detergent that is safe to use on glass, plastic, copper, brass and ceramic. It is safe to handle and environmentally friendly. 2 oz's makes 2-5 gallons of working solution.