A semiconductor integrated circuit device provided with a pipeline A-D conversion circuit in which the enhancement of accuracy and the reduction of power consumption are accomplished is provided. The air gap inspection device may include a substantially rigid rail, a cart positioned on the rail, a drive system for maneuvering the cart along the rail, and an inspection head positioned on the cart. Next, the system ionizes the sample and injects the ionized sample into a laminar gas flow. Each side panel includes at least one stacking tab extending from a top edge of the side panel.