Conforms to EN 149:2001+A1:2009. The Unique Typhoon™ valve has been designed to reduce breathing resistance, heat and moisture build-up. The valve is unaffected by any moisture, and therefore can be used with the same performance under very low temperatures. The fold flat design makes SpringFit™ more compact, and easily pocketed. SpringFit™ is also individually packed to ensure a high level of hygiene. Unique endoskeleton structure. High efficiency (99% minimum) filtering.