I will agree with Hidalgo. I trialed for years with retrievers and trained a lot with no collars. I was much younger then and if I was wearing my "Hong Kong go Fasters" [imported sneakers] I would run out and give the dog a shake and make him sit there thinking about his transgression while I panted my way back to the 'line'.
Then one day I saw a guy with wheel barrow and I thought " That little wheel saves a lot of huffing and puffing, maybe I need an e-collar
I used Tri-tronics for years with much success. Recently I sold my tritronics gear and went with Garmin. I'm very happy so far.
I don't field trial but I do hunt with my dogs, and I train for others. The e-collar , used properly is a great tool. Used improperly it is a big stick.
My wife felt the same about using the e-collar on a dog. She also had knew nothing about it except it shocked the dog. Listening to idiots talk about 'frying' the dog, or 'lighting him up" didn't help.
I had an old English bulldog in for training. Would not listen when it got more than ten feet away. Collar time and hearing improved 100%. I gave "Yes Dear" some instructions on it's use and in one session at the controls she was a convert.
The unit I have has variable shock settings as well as tone and vibrate. After some conditioning a tone or vibration is enough to get compliance. I like this unit much better than the tritronics, and it is about half the cost or less.
I have a 4 year old lab who gets 'deaf' once in a while. He has not had a collar of any kind on him since he was six months old except for training, and not much there. When he goes to deaf and decides he is training me, I put an e collar on him. Immediately he becomes attentive, even though I've done nothing other than putting the collar on him.
Conditioning to the collar is the key. You won't need much more than tone or vibration once that conditioning is done.