You know what this is for! (Castrations)
But it can also be used for ballbusting play, in a controlled environment.
Just don't leave it on your testicles for too long and have some scissors handy.
It doesn't hurt too much while it's on, except for it being very tight around your balls, but the rush afterwards is very intense I've heard ;)
Standard castration device, used for sheep normally.
*Comes with 100 rubber bands*
Material: Stainless steel