Honeywell Willson Supplied-air visor with special comfort features. HSE-TM 14/7.25 Class 2/3 (Equals or exceeds respirator protection requirements of EN270 and EN1835. Nominal Protection Factor (NPF) 100 (Class 2 - without warning whistle) or 200 (Class 3 - with warning whistle). Assigned Protection Factor (APF) (BS 4275:1997) 40. Connects to compressed air supply which must be breathable quality conforming to EN132.