Thanks for the offer. I just spoke to my friend who has these drivers, he is going to dig them out for me. He pulled them out of a movie theatre years ago. He doesn't know what model they are, but told me he thinks they were made about 1950(!) and were rated to about 40 watts RMS.. I'll try and get the model number and let you know. I would guess Celestion only made one type of 18" driver back then?