An auto-darkening helmet line comes in two new series– the Viking 1840 features a 1.8-in. viewing-area height in a compact DINS-sized lens cartridge, and the Viking 2450 featuring a 2.4 in. viewing area height in a U.S. standard 4.5 in. x 5.25 in. sized lens cartridge. The 1840 features externally-controlled continuously variable 9 to 13…