'Osglim'-type decorative neon light bulb. Bayonet cap lightbulb with pip. Letter 'F' filament.
Part of the Bob Gray collection of electrical objects.
This 'Osglim'-type light bulb contains a neon filament in the shape of the letter 'F'. Light bulbs like this are quite rare. They were typically used in advertising signs, for special events such as parties or for marketing. They were used in sets in order to make up words. The donor of this item recalled that in his youth as an electrical contractor these items were so expensive that they were kept in a locked cabinet and only the boss had a key. The pip on the end of the bulb is not normally seen after the mid-twentieth century but these bulbs were made in such small quantities that older techniques were used to evacuate air from the glass envelope.