The (ahem) Golf Sweet Spot Finder locates the optimal spin axis of a ball enabling you to felt tip pen a line onto the ball so that you know where to hit next shot. The ball is rotated in a mechanized chamber and a small hole enables you to insert your felt tip nib and draw the line.
We’re not entirely sure of course restriction on the use of this kind of thing, and you may look a bit daft lining up your Sweet Spot Finder before every tee shot but perhaps you could carry a stock of readied balls with felt lines already drawn.
The Golf Sweet Spot Finder runs on battery power, though, so you could always nip behind the bushes to gain that extra edge. Imagine the look of envy when you’re hitting straight and hard, and putting more accurately.
Oh, and it includes a pen!