scorpy Golf Level Ball Marker with Metal Bead and Hat Clip, High Precision Putting Green Reading Aid Golf Accessories, Precision Alignment Tool for Perfect Putts
Sensitive enough to read slight slopes and optimal for judging the inclination between 0o and +-3o, which is difficult to visually check(more than 3o can be easily distinguished by eyes). The interior is precisely carved by CNC, and unlike light plastic, it has an appropriate weight so that it does not float on the green.