Supplementary Electric Shock Tone Collar for Hidden Dog Pet Fence NE#1 Type: Dog Fence Dog Age: Small / Medium / Large Features: This collar is only designed and workable for our shop's in-ground pet fencing system (Buyer can purchased the system from our shop or contact us for details!) Sturdy nylon collar with length adjustable from 30 to 55cm (approx. 12 to 22 inch) for different size of dog (trainer can fit other collars with a width of 2 cm (0.75 inch)).The collar has battery indicator (LED) which can show the battery status, i.e. GREEN for working properly, RED for battery replacement is necessary.