Pepetools high quality bell jars are manufactured from acrylic for lasting use. 

• Perfectly clear to see through when running a cycle
• Thick, sturdy walls 
• Heavy bottom rim cut ground and smooth to create a perfect seal

Safety instructions:

• For an optimum seal, keep the bell jar rim and vacuum table clean of investment debris.
• Never use a chipped or damaged bell jar.
• Never press or hit the bell jar during vacuum. It's under tremendous pressure and can implode, resulting in dangerous flying debris.