Performed 1 natural gas Rooftop package unit inspection. System has 2-16x25x2 filters. Will need to return and replace. Checked heating system and cooling system. Furnace is 100k btu natural gas system, checked burners and heat exchangers. Furnace is heating properly. Cooling system is 5 ton cooling capacity, checked compressor operation and refrigerant levels. Cooling system is functioning properly.