For short-haired breeds Only fits Educator brand models 300, 400, 500, 800, 1200, EZ Educator, Pro Educator and 1000 E-Fence. Not compatible with BP-504 or BP-504-C Barkless Pro No Bark Collar. Nickel-free titanium is ideal for sensitive skin Use the shortest contact point that makes a reliable connection Do not leave the collar receiver on the dog for more than 12 hours at a time