http://www.flexiusa.com/

Excellent for those long walks in the park. Convient and travels well. Not specifically for training, note the warning from the manufacturer

INTENDED USE

The flexi leash is for use by responsible adults only. Do not allow anyone to use this leash who has not read the Warnings and Directions for Use pamphlet. Keep out of reach of children. The leash is not a toy! To avoid the risk of injuries like cutting, burning, amputation or eye injuries to infants and children, DO NOT USE THE LEASH NEAR OR AROUND INFANTS AND CHILDREN!
This leash is intended to help you lead and restrain your dog. The leash user is responsible for keeping the dog under control at all times. The leash is for dogs that are controllable and well behaved.
UNINTENDED USE

DO NOT use this leash for disobedient or uncontrollable dogs.
DO NOT use this leash for dogs that exceed the specified weight for the leash.
DO NOT use this leash as a stationary (non hand-held) leash attached to a pole or other fixed object. The flexi Garden Tie Out Model is specially designed for use as a stationary leash.
DO NOT use this leash with any product not supplied by flexi USA, Inc. except for the dog’s collar, which must be strong, and in good condition.
DO NOT use the leash near or around infants or children.
DO NOT attempt to operate or use more than one leash at a time.
DO NOT allow anyone to touch or come in contact with the leash cord/tape or all belt (6) while in use. It can cause injuries like cutting, burning and amputations

Pros: protable, can keep it any where. Expands to give dog movement.

Cons: Not really for training.

maybe you disagree but I like my bullies to walk next to me or slightly behind..

I hate seeing a small dog pulling on these leashes coming toward my dogs... I can just about read my dogs minds.. ok come just a bit closer... we wont hurt you...not much...it will be a fast death little yapper.

These leashes have probably caused more dog fights than any other. No control and they will not retract a dog... you must advance on the leash and hit the brake.

I bought one of these when I got my first pit bull.. then petunia saw a cat and I realized... these are not meant for a strong dog.

Pros: none

Cons: might as well forget about the command heal with this

I love these but in the beginning, I had trouble learning how to use this. Now it no problem and I can walk two dogs at once. I may end up buying a third one if you know what I mean.

Pros: You have total control.

Cons: I had trouble getting the hang of this device.

these are wonderful for walking dogs, gives them a little more smelling space

Pros: these are great

Cons: none

This is the second retractable lease we have purchased. The first one (another brand) only lasted a month before breaking. We have had this one over a year and it continues to work well. Our dog isn't large but is strong. This is not a leash to use for training but is great for leisurely walks where your dog is allowed more freedom.

Pros: Durable

Cons: Not for training