Haha my sister has one of those she picked up in the 60s or 70s. My guess is that it is old technology but it's just MY guess. That's my disclaimer so no trolls or augments. hippy new year!
its plastic that was my huge disappointment spending around $250 .i moved them from the 240 led blackstar that was ak 47 .It grew in the phototron for a month and was have 90 plus temps .T12 were in it .