MKS Instruments, Inc. (MKS) is a provider of instruments, subsystems and process control solutions that measure, control, power, monitor and analyze parameters of manufacturing processes. It also provides services relating to the maintenance and repair of its products, software maintenance, installation services and training. The primary markets it serves are manufacturers of semiconductor capital equipment and semiconductor devices and for other thin film applications, including flat panel displays, solar cells, light emitting diodes (LEDs), data storage media and other advanced manufactured products. The Company groups its products into three product groups, based upon the similarity of the product function, type of product and manufacturing processes. The three groups of products are: Instruments and Control Systems, Power and Reactive Gas Products and Vacuum Products. In March 2013, it acquired Alter Power Systems S.r.l.