The key features on a remote training collar are Correction Type, Range, Battery Type, and Number of Dogs.

Correction Type

There are three types of correction commonly used on a correction collar:

• Static Correction - uses a static shock that can be controlled by the transmitter. This is the most commonly used and most effective type of correction.
• Spray Correction - these shoot a jet of citronella scent at the dog's nose. This type of correction is less effective, and works well only in more submissive dogs.
• Ultrasonic Correction - sounds a high pitched sound that is annoying to the dog. This type of correction is the least effective.

More details on the type of correction can be found here.

Range

The training collar system vary in range from around 100 yards to 2+ miles. The range determines how far the dog can go from the transmitter while still getting a consistent signal. The range you need depends on the type of activities you intend to use the collar for:

• Basic Obedience Training - a range of 100 - 200 yards is sufficient for teaching your dog basic obedience training commands such as sit, stay, and come. The upper end of this range allows you to do more off-leash work such as training at the park, the lower end of this range is sufficient for training around the house.
• Hunting (Retriever) - for hunting dogs that are doing retrieving work, a range of around 500 yards is required.
• Hunting (Pointing / Chasing) - for hunting dogs that are doing flushing and hunting, where the dog will be independently chasing the target, a range of 1 - 2 miles is required.

Battery Type

Training collars use either rechargeable of disposable battery systems.

Rechargeable batteries can be plugged into a power socket to be recharged when not in use. There are two competing technologies: Nickel Metal Hydride (NiMH) which is heavier and takes longer to recharge (10-12 hours) and Lithium Ion (Li-Ion) which is lighter and has a shorter recharge time (1-2 hours) but is also more expensive.

Disposable batteries require you to purchase new batteries every time the system runs out of power. This are generally to be avoided. In particular avoid proprietary disposable batteries that can only be bought from the system manufacturer as these tend to be particularly expensive and inconvenient.

Capacity

Transmitters vary in their ability to control multiple collars at the same time. Some transmitters can control only one collar, while others can control up to four collars at a time. Transmitters also vary in their functionality in multi-dog use. In an attempt to economize on buttons, you often lose the ability to use many of the functions on some transmitters when you move to multi-dog usage.