it removed the problem of the spring plug
Marks that can be entered for this maker: Model, type or typology, Model, type or typology, Era marker / packaging.
Nothing predates 1933; components only push the date later.
Sold-price aggregates are not collected yet, so the archive gives no figure — condition, originality of the transformers and a documented recap move this model more than any list price.
Evidence: razors.page — patent archive · razors.page — patent archive