If you do not have saddlebags then the helmet lock works great. If you have the "T" model then it is useless.
I relocated it inside the saddlebag.
Granted if someone wants to steal your $500.00 helmet this would not stop them. My helmet cost only 50 bucks and this mod is just so that I don't have to carry it everywhere when I get off the bike. Sure you could use a big old cable with a lock but that would mean you have to carry an extra key or remember numbers. The lock was already on the bike, I just put it use.
I don't know what size screw and nut I used it was in my box of assorted stuff.
Since I had everything on hand my cost was zero but if you don't it will cost you only a few bucks.
Note: you have to make two holes, one for the screw and one for the nipple on the back of the lock.
And thanks to someone else that mentioned in a post that you have to buy the security bit set ($5.00 @ Lowes) to get the lock off the bike.