Recommended Training Steps: When a dog has bad behavior: 1. Use the Beep mode to warn the dog with sound; 2. If the dog does not react, use the Vibration mode; 3. The Vibration mode can have a good training effect for some dogs and stop their bad behavior. If the dog does not react to the vibration, briefly use the electric shock mode (the intensity is adjustable, which is completely safe for the dog). After receiving different training warnings, the dog can stop its bad behavior every time it hears the sound warning. Generally, you will no longer need to switch to vibration or electric shock modes. Professional Training Collar for 2 Dogs If you have two dogs and need two receivers, you can purchase this product and sync it with the remote control. After syncing, you can use one remote control to control both collars (two dogs). The remote control has two channels. You can sync the two receivers to two different channels (channel 1 and 2) and train your dogs separately. For example,