A spool-type ceramic insulator for electrical installations with the shape of a grooved cylinder. Electrical systems, whether transformers, power or control boards, and old posts needed the use of moulded support or spool insulators of different kinds and shapes. Today they are made in glass fibre or epoxy resin but in the first half of the 20th century they were made in porcelain because it is a highly stable material suited to prevent electrons flowing through them.
These types of pieces were seen in the factory's sales catalogues from 1907 and disappeared in the 1940s. Although significant numbers and volumes were produced, the factory evidently did not believe them to be articles that would identify the firm and therefore did not stamp them with its brand.