I hear the phrase “stationary bark control”. What does that mean?

Answer:

When a product is marked as stationary bark control, it usually means that it is a product that uses ultrasonic sound to correct a dogs barking. The unit will typically have an enclosure containing a microphone, electronics and an ultrasonic emitter. The microphone detects your dog barking and the control circuitry causes an ultrasonic sound to be emitted.

These sounds can be heard only by your dog, not you, and are unpleasant but not actually painful or damaging to your pet, so it acts as a great barking deterrent. The enclosure can be made for either indoor or outdoor use.