Push in fittings are a popular alternative to traditional fittings and are suited for plumbing systems such as potable water, hydronic heating systems, irrigation, and water heaters. No specialist tools are required and they're much quicker to fit than other fittings. Just push the tube into the fitting to create a strong seal. These Straight Female Connectors are used to connect a tube line to a pipe, or pipe fitting, with a male thread.