When used properly, diversionary devices provide significant tactical advantage, reducing the possibility of injury to team members, hostages, and suspects. Diversionary devices are also known as light-sound devices, flashbangs, and distraction devices. They typically consist of some type of canister, a powder charge housed inside the canister, and a fuze assembly. The latter has a number of parts including a safety lever (spoon), a striker, a primer, a pull ring and safety pin that are clipped together, a delay element, and an ignition mixture. When used properly, it creates a loud report and a brilliant light that may disorient and confuse those who are inside the tactical environment. These devices should never be considered as a substitute for good tactics. A fuze is a mechanical device commonly used with grenades. It provides a one to two second delay before initiating the charge. Development of diversionary devices focused on three basic types: a bursting canister, a separating submunition device, and a non-bursting canister design. The traits common to all diversionary devices are bright light and heat generation, a loud noise that can cause injury to unprotected hearing, smoke, and the creation of overpressure. These characteristics combined create disorienting physiological and psychological effects. This provides a window of opportunity during tactical operations. Use of diversionary devices has to be guided by solid criteria for deployment, usually dictated by departmental or team policy. These deployment concerns should be kept in mind: protective equipment for team members, contingency plans for a fire, and whether there are children or elderly people present. The safety pin on the fuze should be prepared for use prior to actual deployment. Personnel assigned deployment responsibilities should have a cover officer whenever possible. A device failure drill is a good idea during tactical use. Medical screening is an important post-deployment concern. Proper documentation is critical since tactical deployment is clearly a use of force issue.