Do you have source that police spend money and have done research and developed on it and not the US military.
I just freaking gave several! Kevlar, when the National Institute for Law Enforcement and Criminal Justice had research into having it used for bullet proof vests back in
1971! The freaking US military did not get involved in that for another decade, long after it was in common use by law enforcement globally. Because I was in the military then, and we did not get Kevlar until the PASGT equipment was first issued in 1982. And it did not see wide-spread adoption until 1985.
Before 1985, we were still using the freaking P-1955 body armor. Made in, you guess it, 1955. That was the vest most well known for use in Vietnam, and used hard fiberglass plates to try and protect the wearer. Yes, we were still using that thing almost three decades later.
MACE, Pepper Spray, add in tear gas, those like this are all crowd control equipment. None of them is of any use to the military, those are all 100% civilian law enforcement equipment. The military might adopt it later, but it has absolutely no purpose on the battlefield. In fact, using things like tear gas on the battlefield is actually illegal!
Yes, the use of tear gas on the battlefield is actually explicitly illegal under the Chemical Weapons Convention. So why in the hell would the military spend a single penny on something they are outright prohibited from using on the battlefield?
Look, I am done with this. You outright ignore anything you do not like, and do no research yourself. That is not how debate works, unless one is a complete mental moron. You use facts and references to prove your point, you do not simply ignore anything you do not like and then challenge others to provide sources.
Especially when they provide sources you outright rejected the first time.