When working at low levels of stimulation on our E-collars, we've noticed that there is an inconsistent output rate--for example, levels 8, 9, and 10 may feel exactly the same to the dog, but level 11 will show a drastic increase in the stim output. The next time you use the collar, the drastic rise may be at level 10 instead. If you determined that your dog works well at level 10, and suddenly he is getting a much higher stim, it can be very disconcerting for the dog, and highly stressful to very sensitive dogs.
This problem is not apparent at the higher levels of stimulation- the higher levels are much more consistent in their output rates. The stimulation reducer will allow you to work at the higher levels (thus avoiding the problem), but the dog will only feel the low level of stim.
This stimulation reducer will reduce the stimulation by 50% and can be used with all E-collars on the market.