This speaker was removed from a Cossor Melody Maker valve (tube) radio, as the speaker was rubbing causing distortion especially at the bass end of the audio. I removed the central dust cap, and found that the speaker only has a tiny (and very weak) magnet, which is held by a nut and bolt in the centre. I was able to loosen it and re-centre it, and glue back the dust cap. But although the speaker now works, it is inefficient, and probably not as good as the (smaller) replacement I had fitted. So I have the dilemma of whether to re-fit this one, or keep with the replacement. As the radio works so well now (and is already not original, having once been painted, and then stripped back to the original bakelite surface), I will probably leave it as it is with the replacement speaker.