45 rpm records and LP records had exactly the same centre hole, for playing on a turntable, when bought over the counter at the record shop... but you were able to punch out the centre of a 45 rpm single so that it could be used in a jukebox

so if you bought ex-jukebox records you then needed one of these to replace the punched out bit for your turntable

not that I was old enogh to buy juke-box records at the time

[now where did I put that diamond ring...]


very nice drawing Bob