Chemistry:PEF rod

PEF rod or PEF backer rod is a flexible polyethylene foam cylinder that is pushed into gaps where there is a construction joint. The joint is usually filled to level with a viscous sealant to provide weather-proofing.

PEF rod typically comes coiled in a box, and comes in various diameters and lengths. As a result of the foam structure, the material is low-density and flexible.