They are very effective, I used one when I was younger on a farm with animals and the band is very strong.
So one day i thought I would see what it felt like and used the proper band and tool, once I managed to get my balls through the tiny band it felt very tight for a few minutes, then by balls started to change colour to a red/pink-purple so I thought it was time to take the band off (as I want to keep my balls).
But I didnt think it would be very difficult so I didnt have any tools, so I started to panic.
My balls were starting to die slowley and I could not do any thing about it, and I could not ask any one for help!!! what was I to say "can you please help cut off the ********** band I have around my balls!!
So I did end up finding some sissors, where I tried to snip the band, but being so tight I sniped my sack also so there was now a little blood!!
So I was now realy panicing with the blood flow reducing from my man hood and now i was cutting my sac.
I found a wodden Ice blook stick and managed to put it on the under side of the band and was able to put the sissors on that and snipped the band, once it cut straight through it wiped around and that was very sore also.
So as to you comment to elastrate a guy who pissed you off, as long as you locked him away from some sissors he wont be able to get it off and you can sit there and laugh as his balls die in front of you with nothing he can do about it.