A stainless steel waste coupling is a plumbing component used to connect a waste pipe to a plumbing fixture, such as a sink or a bathtub. It provides a secure and watertight connection between the fixture and the waste pipe.On the other hand, a PVC waste pipe is a type of plastic pipe commonly used in plumbing systems for drainage and waste disposal. PVC (polyvinyl chloride) is a durable and lightweight material that is resistant to corrosion and chemicals, making it suitable for waste applications.When it comes to connecting a stainless steel waste coupling with a PVC waste pipe, you would typically use a PVC coupling or adapter. This fitting is designed to connect PVC pipes and fittings to other materials, such as stainless steel.