This John Guest stem adaptor fitting is made of acetal copolymer and has stem and NPTF male connectors. This stem adapter fitting is for connecting pipes or fittings with different end types, diameters, or materials in a straight line. It has a stem on one end and has a National Pipe Taper Fuel (NPTF) male connector on the other for connecting two pipes or tubes with different ends. 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). This fitting 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.