The only other "Irv" I know is Irv Miller of West ("By God!") Virginia. He and his wife own and run J & L Self Defense Products. J & L offers an interesting assortment of items at a local store in Morgan County and on the its website.
For the past twelve years, I have drooled over items intended to cause thugs a world of pain with a mimimum of effort. I'm not claiming that a working knowledge of some martial art and human anatomy is not needed. But it's a damn sight easier to apply your expertise with a device that will temporarily blind or shock the living daylights out of an assailant (leaving him or her to lay there in a puddle of drool!).
Why was I claiming to "drool" over Irv's selection of assorted pain-inducing devices? Simple. They're not legal to even own, much less use, in my neck of the woods. I would carefully investigate local ordinances, before deciding to purchase any of J & L's stuff. Irv or his wife will be more than happy to help you out with any questions on this subject.
As I've grown older, I have accrued a few memories of attacks I either witnessed or endured. All of them occured when the assailant was sure there were no witnesses. A number of the devices Irv sells would have saved a lot of time, effort and injury ... that's my perspective on the issue. You must weigh the pros and cons (ooops, faux pas!).