Product Description This acorn cap nut is a hex nut with an enclosed dome and it is partially internally threaded. The dome feature offers protection of exposed screw threads and a decorative appearance as a finishing fastener. The cap nut also protects from injury by covering exposed threads. From the Manufacturer This acorn cap nut is a hex nut with an enclosed dome and it is partially internally threaded. The dome feature offers protection of exposed screw threads and a decorative appearance as a finishing fastener. The cap nut also protects from injury by covering exposed threads.