Founded in 1926, Kopp Glass was formed from the remains of the Pittsburgh Lamp, Brass and Glass Company. The previous company excelled in crafting glass lamps and tableware in a wide array of colors, which contributed greatly to Kopp's quality and success it's known for. Shortly after Kopp was formed, they developed "selenium red" glass, which became the new standard in railroad signals. ---I got this from their website, add whatever else - Pyth---
Obverse Full View
Reverse Pattern Detail
Reverse Upper Rim Inscriptions
Reverse Lower Rim Inscriptions
No Lower Inscriptions
Production Years: 1921? - 1938?
Available Colors: Blue-Green, Emerald Green, Amber, Deep Amber, Red, Deep Red, Clear.
Pattern or Mask of Lens: Diamonds with 4 lines going from the bottom, three quarters up the diamond.
Logo Displayed on Front: N/A
Rim Inscriptions, Front & Back: 8⅜ DIFFUSING RDL NO 27 KOPP GLASS INC. SWISSVALE PA.
Signals Used On: Harrington-Seaberg, Horni, Ruleta, early Eagles, early GEs, possibly 1st gen Marbelite
Available Colors: Emerald Green, Pale Yellow, Red.