The Model 804 Handheld Particle Counter from Met One Instruments Powered by Acoem is a 4-channel portable particle counter that counts particles 0.3 microns to 10.0 microns – giving you portability and reliability at very competitive pricing. Though compact, this unit is completely self-contained with its own internal battery and sample pump. The unit is configurable, allowing you to choose your particle sizes of interest from seven sizes: 0.3, 0.5, 0.7, 1.0, 2.5, 5.0, or 10.0 microns.