Larry, you make a good point about the cost of blast gates and it's certainly reasonable to expect them to be relatively leak free. But the nature of blast gates and how they operate does make it hard to get a hard seal. That gate has to slide to open and close, so it's not a tight fit in the slot it rides in. The leakage is compounded when someone installs them "backwards" so the locking knob forces them open rather than closed. In the end, they somewhat rely on the system's air flow to "seal" them. We can only hope that the "premium" products at least try to do a better job...