I just got a flyer from SOTA Instruments, Inc., maker of: The Silver Pulser; The Bio-Tuner; The Zapper; The Silver Maker; Water O3zonator; and John Skilling's Harmonic Pulser. I thought I'd share their info:
SOTA Instruments, Inc.
PO Box 20019
Penticton, BC V2A 8K3
State of the Art/SOTA Instruments, Inc., makes high-quality products although plans for Bob Beck's boxes are available on the net if you are handy with soldering simple electronics. I'm not up to par myself. Hope this helps and please share the address and toll free number with those who don't have internet access