Multiple color bingo ball set includes balls numbered B1 to O75. Here's a breakdown of the features:

1. Size: Bingo balls have a diameter of approximately 7/8 inches. This measurement refers to the width of the ball.

2. Number: Each bingo ball features a number written on it. The number is typically printed in black, making it easily visible against the background.

3. Background: The background color of a bingo ball is white. This helps provide contrast to the black numbers, enhancing their readability.

4. Clear plastic cover: Bingo balls often have a clear plastic cover or coating. This cover serves to protect the number and maintain its visibility over time.

Overall, these features are common in traditional bingo games and are designed to ensure clear visibility of the numbers on the balls during gameplay.