Yes they can be used on a terrier that hunts away ,they will tell you they are in ground but wont be as good as a terrier loc to dig on to , as they wont be as accurate as i think your talking with getting within 20ft with them
Thanks for that. One more question, would they be a bit big for a terrier,i mean the transmitter if thats what it is,or would it be like a B/Flint ?