At the first bark, a beep sound is emitted. If another bark is detected within 30 seconds, a beep sound and a static stimulation are emitted (light, progressive or strong according to the selected operating mode). If your dog stops barking during 30 seconds, at the next bark, the collar will start its operating cycle from the beginning (beep sound only). The stimulation function can be inhibited selecting "beep sound only" operating mode. Four operating modes are available so you can adjust the product to your dog: beep sounds only, beep sound + light stimulation (sensitive dog), beep sound + progressive stimulation, and beep sound + strong stimulation (difficult dog).