WINOMO Golf Putting Training Cup Hole (Grey) rubber Imported Material: thermoplastic rubber ( TPR ). Hole Diameter: approx. 3 inch 7.6cm. Overall Dimension: approx. 7.8 * 6.9 inch 19.8 * 17.5 cm. Portable, you can turn any room, office, garage, yard or even a staircase into your personal putting green. Allows you to practice your putting anywhere.