A golf training device for improving a golfer’s swing having a weighted contoured head that provides for proper feel of a mechanically correct golf swing. One of the end faces is provided with a projecting convex head, while the other end face comprises a correspondingly formed concave receptacle for the head. When the subsystem can be reset without performing a system wide reset of the communication device, communication device downtime is reduced, which facilitates a positive user experience. When reheat is completed, the blow molds are fully closed and the parison is transformed into a bottle by applying compressed air andor vacuum. There also is provided a process for the preparation of phenylacetic acid compounds 2, wherein R2 and R6 are as defined previously and R5a is hydrogen or alkyl, which are useful for the preparation of pyridazinone compounds.