PVC80CAP1 Schedule 80 PVC Slip Cap, 1 Inch. A cap is a plumbing fitting that allows you to cap off or end a section of pipe. This cap has a nominal measurement of 1 inch and is for use with 1 inch schedule 80 PVC. The PVC80CAP1 has a slip connection, this means that it slips directly onto the desired section of pipe. These fittings are great for water transportation applications such as irrigation and sprinkler systems.