ELI5: Explain Like I'm 5

Cross-linked polyethylene

Cross-linked Polyethylene is a type of plastic made by combining and linking many small molecules of ethylene (a gas made up of two hydrogen atoms and one carbon atom). This process makes the molecules of ethylene strong and very resistant to heat, so it's great for pipes and products that are exposed to extreme temperatures and chemicals. Cross-linked Polyethylene can last longer and perform better than other types of plastic.