Soft silicone facepiece. Includes a negative pressure push button seal check mechanism. Flexible System (gas & vapour and / or particulate filters). For use with 3M Secure-Click filters. HF-802SD includes a speaking diaphragm. Face piece weight:182 g (varies per size and model). All masks in the HF-800 range have the 3M™ Secure-Click™ filter connection mechanism allowing connection to a broad range of 3M Secure-Click filters to protect against gases, vapours and/or particulates depending on your individual needs.