honestly, IMHO, i couldn't imagine using a shock collar on my dogs. they're my BEST friends, and have been there through everything, and i can't imagine using this to "train" them not to do something. i wouldn't want to be "trained" to do my job by bosses using shock therapy, ya know? there are ways to train them without using a shock collar. have you tried them? as far as chewing on rugs and carpets, have you tried keeping them in one room with you, when they do it, take a keychain with bells, keys, whatever makes a LOT of noise and throwing it right at their feet? not at THEM, but right next to, so it scares them, then when they walk away, praise them. if the problem is when you're gone, have you tried the crate option? the keychain idea works also with digging. if they're too far out of range, use a water hose, it's also very effective. when they stop, and come to you, praise them! as for chasing the cat, try teaching them the "leave it" command. work first with treats in your hand, when they smell it say "leave it" and take it away. the next step is to leave your hand open, tell them leave it, then toss it at their feet, when they go to get it pop their leash (not hard enough to hurt them) and tell them leave it. then work to throwing a squeeky toy or something they LOVE a foot or two away, make them leave it. pop their leash if they go for it. make sure to reward them EACH time they do leave it. then go up to bringing the cat in the room (in a crate if the cat runs) and work with the leave it command, while on leash. eventually, they'll learn to "leave it" (the cat.) we did this with ALL our dogs. it works. i really would try these techniques before the shock collar. can you imagine what your best friend thinks, you've loved him / her and they've loved back, and now suddenly for no apparent reason (to them atleast) you're resorting to hurting them. i can't imagine their shock. training takes a lot of time, and effort on your part, but please consider these options before the shock collar. it will take a while (atleast a few weeks) for this to work, and also a lot of work, but it's worth the effort! sorry for the length!