Battery for Overbeck’s Rejuvenator; only available from Grimsby 1934.

An original battery inside a 1934 ‘Popular Model’ of the Overbeck’s Rejuvenator, an electrotherapy device.

Otto Overbeck, with zero medical expertise, sold his Overbeck’s Rejuvenator all over the world. He was quite the marketing genius. Much more information can be found on this website.