Long-path gas cells are used to analyze trace components in gas samples. Typical concentrations may range from percent to ppb levels. These cells feature a folded path design providing an extended pathlength within a compact dimension. Fixed pathlength gas cells from 2.4 meter to 20.0 meter and a variable pathlength cell (1 - 16 m) are available. Cell body materials include stainless steel, nickel-coated aluminum, and heavy wall borosilicate glass. Mirrors are coated with highly reflective gold. Gas cells may be configured for heating up to 200 °C. Heating is often used to prevent condensation of specific components.