I have a petsafe one that I got at Sams Club 13 years ago, but they have them at Farm and Fleet. Also I have collars I got at Home Depot, those vibrates and beeps, then will shock, the vibrate works better than any shock. one word of advice is do not skimp or rush the training, that is the key, once the dog is trained RIGHT it won't even need a collar, 13 years never had the dogs run. another thing is make sure you get their surge protector and ground it properly, I've done other ones only to get them zapped by lightning strikes. Also helps to have visual markings like tree lines or hills, gardens or drive ways, I took a cheap mason saw and divided my driveway so the dogs could not go on the side of the house with the utility meters, Overall system best money ever spent.