"The a correct speaker for a Twin Reverb is the one that sounds good to you. One of mine has Radio Shack Utahs and the other some Celestions I had laying around when I got sick of the JBL D131s. I like the Radio Shack ones better." I used to love those Radio Shack Utahs. I installed those in quite a few amps and cabs back in the day and was never disappointed.