The link for the North 7700 seems a bit expensive, here is a better one:
http://www.amazon.com/North-Safety-7...rds=North+7700
Also, the masks don't generally come with the filter pucks, and I second Hayley on getting the thin ones. I have these ones to work under a clear face shield:
http://www.amazon.com/North-75FF-Pan...rds=p100+north