Features: Make from Acrylic, waterproofs, strong, and builted to bear the rigors of regular use. The built-in bubble Levels on the marker shows you slope & inclines to help with your read. The Golfs marker is heavy enough to lie flat on the putting green, makes adjusting more convenient and accurate. This Golfs marker will tell you how adjust for slope. It’s most useful when you think it’s flat but theres a slight slope. Golfball marker is light in weight enough to carry in pocket during play, and strong enough to provide a quick reading. Specifications: Materials: Acrylic Diameter: about 2.5cm/0.98inch Height: about 0.5cm/0.120inch Package Includes: 1pc Bubble Levels Golfball Marker note: Please allow 1-2cm errors due to manual measurement, make surely that you not mind before order. Due to difference between different monitors, the picture may not reflect the actual color.