42 Scientific, technological and engineering services in the field of physical security, drone detection systems, intrusion detection systems, aerial defenses, and physical barriers, namely, design, simulation, modeling, testing, and operation of physical security systems and systems used to monitor, detect, deter, interdict, intercept, and neutralize land-based and airborne threats; technical consultation services in the field of design, selection, implementation and use of computer hardware, computer peripherals and computer software, commercial surveillance systems, drone surveillance systems for others; online non-downloadable computer software used to monitor and track movement and activity of unmanned aircraft systems (UAS), namely, aerial drones