1.How to lock/unlock:If you want to lock it at a certain distance, you simply push the button down and pull back just a bit, and the leash will lock. If you want to just stop the dog for a second, you simply push the button to stop the retractable feature.If you want to unlock it, push the big button forward. 2.Tangle-free 360 degree tape movement.16ft tape leash with easy-adjust retraction that allows your canine pal to explore but still remain within safe distance.Simple, practical and comfortable. A ergonomic handle fits in your hand well for those long walks. 3.Extremely sturdy 16ft strap---Under 50 pounds for small to medium sized dogs. 4.Note1:Do not let your dog chewing the leash, If the dog leash has a tear in it, it can easily break. Even a very small dog can break it..If your dog likes to chew on the leash, you will need to equip the leash with a bite proof chain. 5.Note2:Do not fully release the leash when the dog rush forward, the strong impact will damage the spring and internal accessories.It needs to be locked in time.If you have any quality problems or other conditions, please contact us.We will give you a satisfactory answer.