Airborne Particle Counters (APC) are used for a variety of purposes such as: • Filter testing • Cleanroom certification and testing • Isolator and minienvironment testing and certification. Often the use of APCs requires the use of tubing for the sampling of the air as the APC may be located some distance from the actual air being sampled. Various factors impact the efficiency of particle transport in tubing. Factors such as sample air velocity, tubing length, tubing material, the number of bends, radius of such bends and tubing diameter need to be considered in selecting and using such tubing.