"Bad Vibes" are often more harmful than viruses, subliminal messages or explicitly discourteous content ("flames") received over the internet. But just what are Bad Vibes? They include, but are not limited to, fraudulent or manipulative intentions, or subconsciously hostile moods on the part of the sender. Such harmful influences can pass through a modem cable as quickly as a hostile glance in a face-to-face meeting. To detect and remove bad vibes, a physical interaction of the greatest subtlety is required. We have found that specially selected quartz crystals, because of their piezoelectric properties and natural birefringence, are best suited for the job. After prolonged heavy use, you may find that one of our crystals loses its effectiveness. If this happens, do not attempt to fix it yourself. Simply return the crystal to us for re-annealing. This inexpensive heat treatment restores the crystal's potency by removing and safely disposing of accumulated internal stresses. It should be noted that our crystals are bidirectional: they remove outgoing as well as incoming bad vibes. We do not sell unidirectional crystals.