Fernco QwikCaps: The Quick, Easy, and Reliable Way to Cap Pipe Ends. Fernco QwikCaps are leak-proof, water-tight, and easy to install. They can help you prevent leaks and improve drainage. This specialty cap offers a quick and easy way to cap pipe ends, test pipes and clean-outs directly over Schedule 40 PVC plastic sockets and hubs. Suitable for above-ground or underground use these caps work great and offer a quick, easy way to cap pipe ends, test pipes and clean-outs. For permanent or temporary projects, Fernco QwikCaps are a reliable solution. Fernco DWV plumbing pipe caps are built to last as they are made of the highest quality materials. With a reputation for quality, innovation, and reliable performance, you can trust Fernco as the global leader in flexible plumbing couplings.