Made in GermanySuitable for all GS150 models of the VS2 to VS5 series and the licensed GS/3 models etc. The compression ratio is approx. 1:12. Only works in conjunction with the long-stroke shaft (60 mm). The head can be installed plug n play. The O-ring seal supplied provides the prerequisite for a good seal to the cylinder sealing surface. The solid construction and the stronger ribbing support heat dissipation. The head also takes into account the piston crown geometry of the currently available Meteor pistons.