Plastic. Hexagonal Shape To Prevent An Overturned Cylinder From Rolling Off 

Manufacturers and Suppliers of Cylinder Measuring Protectors in Algeria, Argentina, Australia, Bahrain, Bangladesh, Belgium, Bhutan, Brazil, Cambodia, Cuba, Cyprus, Denmark, Ecuador, Egypt, Ethiopia, Finland, France, France, Georgia, Germany, Ghana, Hungary, Iceland, Italy, Japan, Jordan, Kenya, Kuwait, Malaysia, Philippines, Tanzania, Uganda