Dipl. Ing. H. Horstmann GmbH is a medium-sized company based in Heiligenhaus near Düsseldorf (Germany). The company was founded in 1946 by Heinrich Horstmann, and since that time it has been a successful family-owned company. Due to its long experience and continuous investment in research and product development Dipl.-Ing. H. Horstmann GmbH is today recognized as a leading manufacturer in medium voltage technology for: Short-circuit and earth fault indicators Voltage testers and voltage detecting systems Earthing devices and accessories. The worldwide distribution is covered by both our own highly qualified sales force and trade agents Our products meet highest quality requirements and are developed and manufactured in own production facilities in Germany. In order to respond to these demands, we have a very high vertical depth of production (e. g. own SMD assembly system) as well as an own research and development department with state-of-the-art testing and measuring equipment. Besides the electronics manufacturing, we have also a mechanical production facility for safety material. Our company has been certified according to DIN EN ISO 9001 since 1996.