A 3-ply corrugated box is a type of packaging box made from three layers of material: two outer layers of flat paper called liners, and a middle layer of fluted paper, known as the corrugated medium. 

• Lightweight: Despite its strength, 3-ply corrugated boxes are relatively lightweight, making them cost-effective for shipping. 
• Durability: The fluted middle layer gives the box its strength, making it resistant to compression and impacts. 
• Versatility: Commonly used for packaging a variety of products, from electronics to food items.