1997EN 379:1994/PRA1:1997 AMD prA1 Specification for Welding Filters with Switchable Luminous Transmittance and Welding Filters with Dual Luminous Transmittance
1994EN 379:1994 Specification for Welding Filters with Switchable Luminous Transmittance and Welding Filters with Dual Luminous Transmittance