it makes all air go downward and would easily keep your glasses and visor from fogging up. I used it for the firs time last night and it's actually more comfortable than you'd think. It's not just for HJC helmets. It comes with the other side of the velcro to stick onto the inside of any helmet.
Although, you should see if your model helmet has its own breath box. This one was like $8 on ebay and $15 everywhere else