Get ready to add a few more golf clubs to the bag – sort of. Callaway Golf launched its new I-MIX drivers this month which allows enterprising duffers everywhere to swap out specific heads and shafts according to course or weather conditions, or just to impress their cronies. The heads are attached to the shaft using a custom torque wrench that provides an audible click and a visual indicator suggesting when it’s safe to let the big dog bite.