A squirt of HALT II Dog Repellent into the face of a vicious dog stops him in his tracks. HALT II is temporarily painful, but medically safe. Effects of the spray usually wear off in a few minutes. Pressure-packed aerosol shoots streams up to 10 feet (3 meter). HALT II Dog Repellent canister clips onto belt or pocket. 1.5-oz. canister. Who knows more about dog attacks than the mailman? So what do the experts use to repel dog attacks? Well, the U.S. Postal Service has been using Halt II Dog Repellent since 1966. You might say they have been conducting field tests for over thirty years. Halt II products use Capsaicin, a naturally occurring extract of peppers, which, when sprayed in a dogs face, causes only temporary, but extreme discomfort for the dog. Think of it as attitude re-adjustment. Halt II stops him in his tracks, giving you time to move out of danger. Halt IIs pressurized spray is accurate up to 10 feet. The attack is interrupted and the animal is distracted from the object of its aggression, thus giving valuable seconds to help the user retreat to a safe place.