This is unusual 3 1/2 fso. Most are 3 fso. Lens is in excellent condition.
RARE Corning Amber 4 1/2" X 3 1/2 F.S.O. 1935 Smooth Lantern Switch Lamp Lens
Vintage 4" Corning Red Fresnel Signal Lens For Railroad Lantern Switch Lamp
Corning 1905 Red 4 1/2" Railroad Lantern Switch Lamp Smooth Lens Glass
Lima L204643 DB Class 59 59003 Yeoman Highlander RARE BLUE RED WITH WHITE ROOF