An insert adaptor, also known as a hose barb adaptor, is a type of steel pipe fitting designed to connect flexible hoses or tubing to rigid pipes. While a combination nipple, also referred to as a hose nipple or hose coupling, is a steel pipe fitting used to connect hoses or tubing together.
Both of then serve a similar purpose of connecting hoses or tubing, however, differences as below:
Connection Type: Insert adaptors are primarily used for connecting hoses or tubing to rigid pipes, whereas combination nipples connect hoses or tubing sections together.
Usage: Insert adaptors are commonly employed when transitioning from a rigid pipe to a flexible hose or tubing, while combination nipples are used when joining two hoses or tubing sections.