I have used them on AR and some other rifles. They were considered to be (some of) the best about 10 years ago or so.
IMHO they are well made and work good. It's 2" long and diam is .920", so it has no military application (it's too fat for the M9 bayo or for the rebar cutter to fit over).
It is a combination muzzle brake - compensator, it has 6 ports (3 chambers), the 2 ports closest to the muzzle are elongated upwards so it counteracts muzzle climb.
As long as I know it's legal for IPSC and USPSA.
It works good for rapid fire, but today there are few others with much better performance IMHO.
It's production made today and sold by DPMS and others.
I'd say you won't waste your money, Brownell's price is $50, you can't find many cheaper brakes today.
Edit to add: Love your signature
