With a similar project, the inspector told me that use of one-way vents are now accepted practice, but I'm on a sewer, and I was inquiring about a vanity vent. Code may be different in your situation and area. I'd find out and not by reading the box. I was also advised to avoid the cheap models. My project is not that far along, and I may go ahead and vent the old-fasioned way. My inspector is more comfortable with that, but code is code, so he can't say no to these new-fangled devices.