Cobalt blue clip-on lenses by Fendall
Cobalt blue clip-on lenses can be used to shield the eyes from excessive ultraviolet and infrared rays. These rays can be emitted when one is welding metal, blowing glass or working at a metal foundry.
This specimen was made by a company called Fendall which no longer exists. Fendall was acquired by Dalloz of France and later by Honeywell Safety products.
The frame’s front bridge is signed Fendall. The lenses each have a marking at their edges of f5H.
These cobalt blue tinted lenses admit very little light and would not be useful in day to day activities.