DESC: The Stubborn Add-A-Dog collar has higher intensity stimulation in the receiver for dogs that need a little extra encouragement. The Field Traner SD-400 can control up to three 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. Have standard Add-A-Dog collars will work with both the standard and stubborn model transmitters. Stubborn collar is slightly larger than the standard. Collars