Rectorseal 84016 3.5-Inch Wall Inlet, White Assures complete flexibility of installation Professional grade ducting, protects and hides unsightly mini-split linesets in a snap Fortress is perfect for mini-splits, high velocity and conventional split air conditioning systems. Fortress protects lineset, wiring and drain hose from weather, vandalism, pet and pest damage. Fortress installs quickly, and can be easily accessed for repairs or replacement of the lineset.