Needle Valve Manufacturers in USA Valvesonly are the best Needle Valve Manufacturers in USA. A needle valve is a type of valve used to precisely control the flow of a fluid within a system. It consists of a slender, tapered needle-like stem with a sharp point at the end that fits into a corresponding seat or orifice. The stem is connected to a handle or wheel that allows the user to adjust the position of the needle within...