SpecSeal Quick Clip Field Installation System is designed to accelerate the installation of curtain wall insulation for perimeter fire barrier systems. The system's unique U-brackets clip onto the mullions without direct attachment by screws to support the curtain wall insulation. Self-locking fasteners secure the insulation panels in place. Each U-bracket has a receiving slot to lock an "L-shaped" stiffener channel in place without the need for mechanical attachment by screws.