Special extractors

Class H extractors, for the work where the dust is the hazard rather than the mess — asbestos, mould, and other carcinogenic or pathogenic material. Class H is a different regime, not just a finer filter: the machine monitors airflow and warns you if it drops, and the bag is designed to be closed and removed without releasing what's in it. Where H is required it is required by regulation, and an M-class machine is not a substitute regardless of how good its filter is.