Both Military and domestic police forces use FlashBangs as entry devices, often called distraction devices. They allow for safe entry in situations where the occupants may be armed as the function of the devices gives the entering forces a few seconds before occupants gain their senses and reorient to their surroundings.
It is unfortunate though that the pyrotechnic nature of the FlashBang also has caused injuries and deaths. Injuries actually to a police office at least on one occasion.
To create a valued distraction intense enough but yet relatively safe, I have devised the Hi Frequency Entry Device. This unit contains a high pressure standard Helium Cartridge which is actuated as it passes through a window pane or thin door and emits a high frequency whistle at a very high amplitude which is disorienting and discomfiting at a frequency chosen to be one which cause feelings of doom or unease. The amplitude using the Hartman whistle is very high. The frequency of 19.5 KHz is know to cause this feeling of unease. It is brief in this application and is not likely to cause any but a brief reaction.
Another form of my invention using a very small pyrotechnic starter with a built in delay is possible and would not require have to be launched through a window pane or door.
Using my invention should not permanently incapacitate potential perpetrators, but also give police and military an effective entry distraction device.