Stainless Steel Pipe Nipple is a small pipe with threaded ends that is used to join two other fittings or pipes. The length and diameter of the connecting pipe are very important in plumbing, heating, ventilation, and air conditioning (HVAC) systems where pipes need to be brought together. Stainless Steel Pipe Nipple is available in a variety of lengths, sizes, and materials, including, among others, brass, copper, black steel, and stainless steel. Depending on its intended use and application, it can have one or both ends threaded.