scope:

This commercial item description covers a Dry Filter Unit (DFU). The DFU is an ambient air sampler that can be used to collect airborne biological particles. Those particles may be transferred to a liquid medium, and analyzed for the presence of possible biological warfare agents. The DFU is available in two types or configurations. The Type I DFU (also known as DFU-1000) is intended for use in most environmental conditions. The Type II DFU (also known as DFU-2000) is intended for use in nearly all environments. It is better suited for operation in special environments in which air is laden with precipitation, sand, or debris. Both DFU sampler types may operate indoors or outdoors in military and non-military applications.