The slip collar, commonly miscalled a choke collar, is available in various styles, most people will associate the chain slip collar as the primary training collar. Slip collars are available in all types of materials from chain, cord, elastic stretch (bungee cord), fabric, flat strap, and safeties.
“Choke Chains” are not intended to choke your dog! The intent is that when the collar is tugged it will pinch the brachial nerve in the dogs neck (much like pinching the funny bone) or according to some people it is intended to simulate how a mother will nip a puppy on the neck to correct it. The Slip Collar is NOT intended to choke your dog. If your dog is choking with the use of this collar then use a different collar!
Personally I don’t care for chain or cord slip collars. They are far to often considered as the only choice and used as the first or only training collar, when a different collar would be more appropriate, safer, and much easier to use. Chain slip collars should NOT be the first choice for a training collar. NEVER use a slip collar, chain or cord, on a dog under 6 months old. NEVER EVER.
If you are going to use a slip collar; be it chain, cord, leather, or strap, learn how to use it properly before you put it on your dog. Do some reading. Watch them in use. The first consideration is size. A collar that is too large will only detract from its primary effectiveness. Measure the size of your dogs neck high on the neck, not close to the shoulders. Then add an inch or two. That will be the size you want to buy. The proper fit should just slide over the dogs head without unduly pulling on the dogs ears.
Don’t buy large thinking “they’ll grow into it”. Instead buy 4 collars, one the correct size and another 2 inches larger and 2 other types of training collars in the proper size. Use the collar which gives you the level of correction you need. There is nothing that says you have to use one collar and one collar only during training. 
If a collar works during training for Sit/Stay but doesn’t work during training to Heel feel free to move to another collar. Switch back and forth. There is a benefit to this in that your dog will not become collar smart.
There are only two ways to put a slip collar on. You’d think people would get it right 50% of the time by chance, this doesn’t seem to be the case. The free end which connects to the lead should be over the dogs neck not under. The position is important, over the neck the collar immediately releases pressure when slack is given. Under the neck this is not the case.
In use there should be no tension in the lead and approximately six inches of slack, the collar should be completely relaxed. Giving corrections with the slip collar should be short tugs. DON’T haul back like you’re setting a gaff in a fish. It is very easy to damage the dogs throat. DON’T let your dog run and hit the end of the lead. DON’T hold steady pressure on the lead constricting the dogs breathing. NEVER yank on the lead in anger. You can crush the dogs throat and kill them. Yes, sad to say it does happen.
If the dog is hauling on the lead and choking. GET A DIFFERENT COLLAR.
The slip collar is a training collar only. It should be on your dog only when training and under your direct control. If your dog is running free and having a blast being off lead then it shouldn’t be wearing a slip collar. I have seen a dog, wearing a chain slip collar, run and jump through a brush pile. The free ring got caught in a branch effectively hanging the dog. In this instance the owner was close enough to see what had happed and immediately rescued the dog, this is not always the outcome.
Remove the slip collar as soon as you are done training. Slip collars should never be on dogs that are tied outside. The dog is not under your direct control when tied out. Remember it is easy for a dog to back out of a slip collar.
A slip collar, in all its various guises, is still just one of many training tools available to you. Don’t be afraid to try different ones. Half the fun of owning a dog is all the neat things you get to buy and try. Use the minimum tool to get the behaviour that you desire. Be realistic in what you are demanding from your dog as well.