Line M Up Pro Precision Ball Alignment Tool snaps onto your golf ball to allow you to easily and accurate add alignment and identification marks. There are many different marking options that allow for a variety of uses. Use your marks to align your shot or tell if your putt is rolling straight. Line M Up also works great to add unique identifiers to you ball. Includes 2 Dri-Mark Golf Ball Markers attached for easy and convenient marking. Conforms to USGA rules and is legal in competition to hel