Shipping paper corner protectors, also known as cargo corner protectors, carton corner protectors, etc., are protective devices used to protect the corner parts of goods during transportation and storage. These corner guards are usually made of cardboard, plastic, or metal to prevent damage to the corners of the box, thereby protecting the goods within the package from damage. Here are some common shipping paper corner guard sizes:

1. 40mm x 40mm x 3mm: This is a common size of paper corner guards, suitable for the protection of light cargo, such as documents, books and light electronic equipment.

2. 50mm x 50mm x 5mm: This size of paper corner protector is thicker and stronger, and is suitable for the protection of general goods, such as furniture, home appliances and general merchandise.

3. 60mm x 60mm x 6mm: This size of paper corner protector is more suitable for heavier or easily damaged goods, such as large electrical appliances, mechanical equipment and heavy packaging boxes.

4. 75mm x 75mm x 8mm: This is a larger and thicker paper corner protector, usually used for the protection of heavy goods, such as building materials, industrial equipment and automobile parts.

5. Custom size: According to the specific size and weight of the goods, custom-sized paper corner guards can be made to ensure the best protection.

The dimensions of paper corner guards are usually customized by manufacturers according to customer needs to accommodate different types and sizes of goods. Choosing the appropriate size of paper corner protectors is important as it can help reduce the risk of damage to goods during transportation and storage.