A ping pong ball is a lightweight, hollow sphere made of plastic, typically measuring 40 millimeters in diameter. It is designed for use in the sport of table tennis, where players hit the ball back and forth across a table using small paddles. The ball is usually white or orange and has a smooth surface, allowing it to bounce easily. The standard ping pong ball weighs about 2.7 grams and is known for its high bounce and speed. It is filled with air, which contributes to its lightness and makes it easy to control during gameplay. The ball's design and material help it withstand repeated impacts during matches.