Safer ground. studio pot id

Hi does anyone know the marks on this one can't find it in data base. Found with number of others including Bob Dawe piece. Thanks for any info.

Hi Naomi thanks for that, I was seeing j not f. Yes spent bit of time this afternoon and have found some very similar ones to this and a couple of the ones in back ground too, although one of these isn't signed. On the coils, I've not seen any thing like that so far but will continued to look, thanks for lead there

Ok thanks Naomi