The SWT series is a sunsep™ hollow fiber encased in a protective resin mesh. This structure protects the sunsep™ hollow fiber membrane while enabling efficient moisture exchange with the ambient environment. The humidity differential between the ambient air and the inside of the membrane drives the dehumidification or humidification of the sample gas at micro flow rates, without the use of a purge gas stream. The SWT series is commonly used in breath analyzers, metabolism monitors, etc.