Elastomeric compression rings and flexible, phthalate-free PVCsealers connect Service Weight Cast Iron Hubs, Extra Heavy Cast Iron Hubs, Clay, Plastic or Steel pipe to Schedule 40 Plastic, Thinwall Plastic, Steel, Extra Heavy Cast Iron or Service Weight Cast Iron pipe in sewer and DWV systems. For non-pressure, gravity flow applications only. Recommended for underground installations. Easy to install and reuse.