$100 for sets of three.
These devices were very effective in suppressing noise created by the motors of my refrigerator, furnaces, and most importantly the AC power line in my office. Switch power supplies were the most contaminating to my entire home. One sufficed for the motors but the AC lines for media and computers required three in a chain upstream of these components.
I have since gone to a large isolation transformer, that is typically used in hospital OR settings.
I am selling these in sets of three.
Buyer pays for nominal shipping costs. $10.
The quad cell antennas in theory help with RF radiation.
