You can sometimes find rare theremins on eBay. Good luck!
"lindo mueble! all in one"
"tocar musica es respirar"
"didder - what would you like to know? This is an original Big Briar Etherwave. Big Briar was the name of Bob Moog's company before he won back the na..."
"Hi, can anybody tell me something about this Theremin, Thanks cu Didder"
"Also for the Open.Theremin v3: https://www.youtube.com/watch?v=8bxz01kN7Sw"