This Supertech manganese bronze exhaust valve guide is specified for BMW N55/S55 engines with a 6.0mm stem and is sold as a single unit. The description identifies it as an exhaust guide and lists the engine family and stem size, making it suitable when replacing worn guides during head servicing on the noted BMW platforms.
Supertech BMW N55/S55 6mm Stem Manganese Bronze Exhaust Valve Guide - Single (Drop Ship Only)