No matter how light any of these gizmos feel in your hand, when you attach them to a golf club they change that club’s swing weight. So what you’re measuring isn’t exactly the same as what happens when the device isn’t attached to the club.

I’m not going to call out any brand by name, but suffice it to say that there are several products out there that attach to the shaft either at the butt, or just below the grip. They weigh somewhere between half and ounce and an ounce.

There are approximately 28 grams in an ounce.

If you know anything about club dynamics you know -- that's a lot of weight to add to the club!

Club making books will tell you that 2 grams in the head changes the swingweight by a point. You’ll need about 4-5 grams to do the same thing when adding weight through a heavier grip.

I have always been sensitive to changing swing weights on my clubs, which is one of the reasons I own an industry standard Mitchell Equipment swingweight scale (read review). So in order to test the effect that clipping an electronic device onto a club might have on swing weight, I took out a 5 iron, measured out 20 grams -- splitting the difference between ½ ounce and 1 ounce -- and attached it (in the form of two triple A batteries below the grip). Go figure, the swing weight changed from D2 to C9. A full 3 points.

GolfSense attaches to your glove

Much more dramatic, when putting the same amount of weight at the butt of the club the swing weight is lowered even more, to C5. That's nowhere near what you're actually playing.

The wafer-thin, and "so light you don't even know you're wearing it" GolfSense device is unique. It attaches to the velcro of your golf glove, providing information on your swing plane, hand position (and much more) through a blue tooth connection to an iPhone, iPad, or Android smart phone/tablet.

It doesn't change the weight of your club, provide any visual distraction or wind resistance. To learn more and watch an amateurgolf.com video review, click here.