The HeS 30 (HeS - Heinkel Strahltriebwerk) was an early jet engine, originally designed by Adolf Müller at Junkers, but eventually built and tested at Heinkel. It was possibly the best of the "Class I" engines, a class that included the more famous BMW 003 and Junkers Jumo 004, but work on the design was stopped by the Reichluftfahrtministerium (RLM) as they felt the Heinkel team should put all their efforts into other designs.
The HeS 30 was designed before the RLM introduced standardized naming for their engine projects. It was assigned the official name 109-006, and it was sometimes called the HeS 006 as a short form. Development ended just as these names were being introduced, so "HeS 30" naming is much more common.