Ball Marker X2 is the ultimate multi-tool. The BMX2 is a ball marker times two. It can be used to produce a line around the equator of the ball AND as a smart ball marker on the green.
Steal time, and play fast. Using the BMX2 actually save you time as you read the green during the time you mark your ball. When it is your turn to putt you can just place your ball in front of your BMX2 with the line on the ball exactly coincided with the line on the ball marker. It's easy and very effective! Of course, you need to lift your ball marker from the green before you play.