Firstly, I'd like to say I have no connection with this company other than having bought one with my hard earned as I liked the look/sound of it and it was UK made. So this is just my view, OK?
First viewing I had was when trawling through eBay as you do looking at theremin related items. It's known as the LV-3 theremin. Neat, small case, 3 variable control knobs; line out volume/mute, volume loop control including distortion effect if required and pitch antenna field of course.
Can be 9v battery powered too as well as powered by the optional A/C to 9volt transformer which is good. I am playing around with mine & have it set up through a battery powered effects pedal (Zoom G1XNext) and 9 volt battery powered Mini Amps (Marshall MS-4 or an MS-2). Have a video camera bag I also bought on eBay that takes all the kit and even has a pair of straps external to the case that takes the folding mic stand which was originally for a camera tripod use I think. Trying to make a totally portable, non external power supply theremin rig. Think I'm almost there!!!
I have slight issues with these non grounded mini amps which alter the pitch field but have got just enough pitch field alteration available to be able to compensate for this and I have tested/used a wrist strap and grounding lead to the audio lead which puts it all back into the usual frame of reference. Fantastic bass response etc.
Works out at about $163 inc. a 110 power supply delivered to your address in the States. Seems good value to me. Have to say I like the sound quality. OK, the sound is compromised through mini amps but through my grounded Ultracoustic Behringer ACX450 it's superb. The Mini Amps sound is the price you pay for a TOTALLY portable battery operated rig, but it's still not bad.
There is a YOU TUBE review here by Mr T Grillo esquire.