Smart dogs can get this collar off
596310
I had high hopes for this collar.  I was excited when I found it on Amazon.  My dog has a large neck and small head so every collar that we have gotten her comes off.  She is a good dog, just lots of energy.  We like to put her outside on nice days because of her energy near her new dog house but we haven't been able to find a collar that will keep her.  So I read through all the reviews and thought this is the one.  The collar fits her neck fine.  However, if she stays in front of me the collar works fine, if she is behind me and lowers her head the collar comes off.  I was so disappointed because I can't even walk her with the collar either.  She is smart and once she realized it would come off that way it was hard to keep it on her.  I didn't want to get a pen because we have a cage in the house, but it looks like I will have too.  So if you have a smart dog, they can get out of this collar.
3514139
My mini Aussie, in a burst of energy, broke her leather collar. The 1-inch wide leather just split apart. A friend told me her daughter used this collar for her larger, often feisty dogs. So I ordered the green. It's lighter weight, very strong, and so far it's effective. I will update if I have any problems with it.
1877455
Dogs have them on, we are still having aggression issues.  Time for a trainer. Will keep collars on, it can't hurt
2354292
great collar but I wish it would separate on the black strap so you can put around the dogs head. If you want to do that with this collar you have to undo the prongs like a regular prong. Me, Personally I unclip and reverse the prong and slip over the dogs head and then reverse back into the neck. Not too complicated but I do prefer if the black section totally unclipped.  Always used a heavier duty prong for my big dogs, but my trainer showed how a lighter one might show more results, especially like my dogs that once you put any prong on her, they behave asap.
1895543
Good training collar. I think it's better than the fully chain on. Less likely to pinch skin or hair.
I do wish that it was made with a quick release clip. I do not like to leave these on my dogs as they play together when there in the house. They are fairly hard to remove each time I'm done walking my dogs. Removed -1 star for that.
2131500
Not really working well, dog is smarter than collar, if she shakes her head enough the collar will slide to one side or the other allow her to bark away
609556
We have a 90-lb Chocolate Lab, who has managed to escape every invisible fence (even with subsequent training). We had purchased every type of collar available, including a harness-type collar, to keep him on his long lead in the yard, but he always managed to escape. Dash's "walkabouts" caused problems with our neighbors, and he was putting himself in danger running around the streets.

Then, we found the Don Sullivan Perfect Dog Command Collar! He cannot get out of this collar! Dash is now safe in our yard until we can get a fence. Dash is very energetic and smart, so it's always been a challenge walking him on the leash, but this collar has been great in training him to behave better on the leash.

This product is great if you have a smart stubborn dog!
4489181
Very happy. This is the ONLY dog collar that my dog does not try to get out of, and happily obeys in it. It is easy to put on and take off. Let me say that again: It is the EASIEST collar to put on and take off. I've spent all kinds of money, on all kinds of collars, and my "Houdini" dog wiggles and squiggles and gets out of them all, except this one. The pet shop sold me their "best collar" and told me it would be impossible for a dog to get out...until they saw my dog escape in seconds. So, if you want a collar that is basically hassle free, comfortable, inexpensive, and actually does the job, this is the one. I've gone back and purchased 2 more colors, it's that good. BTW, my dog is a medium sized "cavapoo" (REALLY smart poodle/King Charles Cavelier), and weighs about 35-40 lbs. I bought him a size large which was tight, so feel the XL fits him better.
1826639
Good quality, only problem is it's easy to accidentally unlatch the clip if you grab the dog by the collar and mistakenly grab the buckle. You will be left holding the collar while your dog takes off. I still use it, but I try to be more aware of it if I need to grab his collar.
1744138
This is exactly what I was looking for. I have a blue heeler 8 month old that thinks his way is the right way- always. I knew he knew what no meant as he is a super smart dog, but this collar has been a good reminder for him. As strong headed as my pup is, he is still fairly sensitive. I usually have it set between 2-3 (which I have tried out on myself and it is just a slight shock) and that does the trick. It has come in really handy while training him around cattle as well.

Just as a heads up... we have had extremely cold weather where I live recently and I realized that his collar turned off at one point due to the harsh temperatures.
1500710
This collar has been a great addition on walks with Lucy, our 65 pound boxer.  She was already trained with a remote fenced in yard, which made it very easy to use on walks.  She is aware of a charge but only needs the beeper for kind reminders to "come."  She obeys all commands, but with the beep she is in complete control around other dogs, too. And it is a good tool to stop her from digging in the yard.
3433439
This collar has really helped convince my dog to get her furry self in the house when she is called.  Either she does not understand English or she is tone deaf.  Or may be she is just stubborn.
But whatever she has learned not to jump fences, not to run the other way when called. She has also learned not to
grab the loaf of bread and run outside to share it with the birds.  It is easy to use and adjust the settings for what ever
works with the individual dog. I use the sound and that works fine for her. When the battery gets low it will emit a beeping
sound and she comes running into the house to let me know something is wrong with her collar.  Smart Dog.
4335701
Collar has nice sleek look, but if your dog pulls on a leash, I wouldn't recommend; the pulling just loosens the collar.
4088339
This E-Collar works pretty good for the most part. My dog is able to get it off his neck, so I have to keep putting it back on, but it's a hoot!! He looks so funny getting it off of himself!
2626665
This collar hasn't gone off accidentally nearly as much as other collars I had. It can be used as vibrate only, and works well. The rechargeable battery is a must for collars- WELL WORTH THE MONEY!
3869016
I have a big lab.  She responds well to these pinch type or gripping collars. This is a very good quality collar. My dog  responds well to it.  She is very aware that the collar is on her.  Smaller pinch collars tend not to make an impression.

I don't see the need for the weight added by the quick release as these colars should not be tight on the dog. It looks like it will last forever, but it is so heavy that it hangs below her neck, when I would prefer the clasp and leash ring to stay at the back of her neck. (the picture of the one I purchased was not accurate.  It did not show the release clip.  Perhaps it is a picture of an older version) I always just slip it over her head rather than mess with the release. I also feel that I need to take it off of her when I am not walking her because it seems too much for her to lug around. It is probably for the best, though as it is safer for the dog.
364553
We borrowed the Zen Collar from a neighbor. We have a foster pet who had just been neutered and the collar worked very well. Much nicer than those hard plastic cones. However I had to buy a replacement for my neighbor. Once the dog was healed we inadvertently left the collar in a place where the puppy thought it was his newest chew toy. LOL