These counters are completely transparent, making them perfect for overhead projectors. These counters are great for learning counting, sorting, grouping, addition, and subtraction. Good accessory can combo different shape, training kids imagination ability. Made of good material, the bingo chip is durable, safe and health. The diameter of counting chip is 19mm, the thickness of counting chip is 2mm. It is great for learning, classroom, kindergarten, home, etc. Item Name: Bingo Chips Material:Plastic Size Details: Size: 19mm x 2mm/0.75" x 0.08" (Approx.) Notes: Due to the light and screen setting difference, the items color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 100 X Bingo Chips