The Walthers Cornerstone HO Scale Roof Details set includes parts to add realism and interest to the most visible part of your structures. This set of building details includes parts to build the details in the list below. All parts are molded in gray. Use these Roof Details to add interest and detail to your Cornerstone HO Scale industrial buildings. 1 Large rooftop air conditioner 1 Medium rooftop air conditioner 1 Small rooftop air conditioner 2 Small swamp coolers 1 Motorized blower 4 Cyclone vents 4 Short monitor vents with round base 3 Tall monitor vents with flanged stack 2 Capped exhaust stacks 3 Motorized vents 3 Wind direction vent-intakes 3 Angled exhaust-Intake ducts 4 Short T-style exhaust stacks 5 tall smokejacks with caps