E-Loc® couplings feature a strong PVC outer shell with a flexible polyurethane elastomer inner sleeve. This unique lining enables both smooth and corrugated duct to be joined together. E-Loc® couplings provide a watertight and airtight connection that will not separate under normal installation. Available in 3/4 to 6 in standard iron pipe sizes (IPS) plus 1 in and 1-1/4 in corrugated.