This BBHardware B01SB BBAHI Cairo and Porto Satin Brass Adapter Block for Pivot Hinges is commonly used with our Cairo and Porto Series Hinges (Prima Series (not Junior or Senior), Cardiff, Shell, and Rondo Series). The Adapter Block allows the hinge to be mounted directly into the Shower Deluxe Header Assembly and can be adjusted laterally to any position required. The Adapter Block has a clearance notch which allows it to fit under the wall bracket when the hinge is mounted close to a wall. A drilled 3/16" (5 mm) hole in the header is required for installation and the hinge base plate must be removed to mount the hinge to the header. Each Adapter Block is individually packed with a screw.