The 4 hole - dual hand lift-off hinge acts as both a right and left hand hinge. It is a stronger option that has a countersink on both sides to allow for right or left hand use. The 4 hole - dual hand lift-off hinge is commonly used to connect T-slot profiles.
For technical details and images, please search for the product using the 80/20 interactive catalogue found here: https://catalogs.8020.net/80-20-Catalog-26/C/.