Polished stainless steel enclosure provides the highest resistance to particle and microbial attachment, it is static neutral, and is easily cleaned and sanitized per ISO 14698-1. The CI-95A therefore provides unsurpassed resistance to bio-contamination. Per ISO 14698-1, Section A.3.2, the internal exhaust incorporates a HEPA Filter that eliminates reaspiration of the exhaust, and subsequent contamination or biocontamination of the environment being sampled.