Check out the Garmins, they bought out Tri-Tronics and some of the older models are not available anymore. "I have an older model and have to buy used items for it" but proceed with caution. You can ruin a dog if you are not familiar with E-Collars trust me when I say that. If I had a dollar for every mistake I made with a E-Collar I wouldn't have to work. Anyhow, it's common sense and start at the lowest to see what works. I'm sure it will all work out. Good Luck.