Paper corner protectors, also known as cardboard corner protectors or edge protectors, are commonly used for protecting the corners of items during shipping, storage, or transportation. They come in various sizes to fit different types of products. Here are some common sizes of paper corner protectors:

1. Small: Typically ranging from 1 inch (2.5 cm) to 2 inches (5 cm) in width and height.

2. Medium: Usually between 2 inches (5 cm) and 3 inches (7.6 cm) in width and height.

3. Large: Generally between 3 inches (7.6 cm) and 4 inches (10 cm) in width and height.

These are approximate sizes, and specific dimensions may vary depending on the manufacturer and the specific application. It's important to consider the size and weight of the item being protected to ensure that the corner protectors provide adequate support and cushioning.

When purchasing paper corner protectors, it's recommended to check with the supplier or manufacturer for their available size options to find the most suitable ones for your specific needs.