The instant application discloses, among other things, a specific set of cutting proportions tailored for the optical characteristics of Silicon Carbide Asscher cut gemstone. The decorative fastener uniquely includes a threaded fastener for securing the license plate to the vehicle and a decorative cover that can be quickly and easily connected directly to the head portion of the threaded fastener. Power provided through a USB connection may be used to power the fans to avoid a need for batteries. The interconnect mechanism is rotatable relative to the frame between a use position for the helmet-mounted device and a stow position for the helmet-mounted device. , R5 is independently in each occurrence a C1-C6 alkyl group etc.