An aerial pen raised and lowered by a driven land vehicle has sidewalls defining an open bottom, a retractable platform for a targeted animal to stand on, a livestock head gate, and a retractable crowding gate cooperatively arranged with the deployed platform and head gate for securing the targeted animal for aerial carrying. This catoptric optical system has plural optical curved reflective surfaces. The selected entity can be received on a network-based transaction system. The first mode is to secure the lower and upper joints against adjustability. The coils are arranged in directions of canceling DC fluxes generated by the coils, so that it is possible to greatly reduce the DC bias magnetization of the core, the volume of the core, and core losses, thereby achieving higher efficiency in the overall apparatus.