Medical Blister trays differ from Pharmaceutical blister packs in that these are not push-through packs. The thermoformed base web is made of a thicker plastic sheet, generally between 500µ to 1000µ and can not be collapsed, thus forming a solid tray. The lidding film provides a peel-open feature and is generally porous to allow sterilisation. Such medical blister packs are used for medical devices, used in hospitals.