I use this on my Honda Valkyrie. Most of the time I just use it to hang the helmet on while the bike is in my garage, or if I park somewhere that I'm not worried about it being stolen. I installed this on the clutch handle. Good fit, easy install.
As you can see, the lock is tiny. It could be cut real easy. But of course, so can the D-rings, or the strap on the helmet, so a much bigger lock doesn't accomplish much. If you buy this to lock your helmet, make sure you put the lock on above the D-rings, but in the center curved area. The lock will fit in the groove at the very top, but if you lock it there, the D-rings can be wiggled over the lock.