The Stubborn Add-A-Dog collar has higher intensity stimulation in the receiver for dogs that need a little extra encouragement. Control additional dogs with extra Add-A-Dog collars. Receivers are waterproof and submersible. It uses rechargeable, replaceable ni-mh batteries and has low-battery indicators. On and off switch on receiver. Will work with any Field Trainer transmitter. Includes both an orange and green collar strap.