This John Guest union tee fitting is made of acetal copolymer and has tube connectors. This union tee fitting is T-shaped and has three female openings to connect and branch three pipes, two on the main run and one branch at an angle from the middle of the tee. Pipe dimensions for tees are represented as A x B x C. "A" and "B" indicate the main run on the fitting, and "C" indicates the branch. It is a push-to-connect fitting that accepts the insertion of nylon, soft nylon and polyurethane tube fittings. The fitting is made of acetal copolymer plastic, which has low moisture absorption, high tensile and flexural strength, and is hard and fatigue resistant. The working pressure for this fitting is up to 150 pounds per square inch (psi), and it meets National Sanitation Foundation (NSF)/American National Standards Institute (ANSI) standards 14, 51, and 61 for plastic piping systems, food equipment materials, and use with drinking (potable) water.

Pipe fittings are components used for connecting, terminating, controlling flow, and changing the direction of piping in many different industries. Push-to-connect compression fittings do not require tools or sealants, and are useful in installations where a heat source, such as a soldering torch, is prohibited. When purchasing pipe fittings, consider the application, as this will affect material type, shape, size, and required durability. Fittings are available threaded or unthreaded, in many shapes, styles, sizes, and schedules (pipe wall thickness).

John Guest manufactures push-to-connect fittings and pipe and plastic plumbing systems. The company, founded in 1961, is headquartered in Great Britain and meets International Organization for Standardization (ISO) standard 9001.