1. Many grills have obstructions such as  stop tabs, rivets and screws.  You want to make sure you take your measurement from   in between these objects and subtract 1/4 inch, so the air filter will fit between them when you put it in.

2. Because our air filters feature a patented Patented Anti-Bypass Seal , the filter does not have to fit edge to edge tight. As long as your measurement is larger then the inner lip of the grill, your filter will seal properly.    Leave yourself room to remove and re-install it easily.

3. Always open the air filter grill to take the measurement, don't assume the inside measurement is the same as the outside.

4. Do not take your measurement from your throw away type air filters.  many times the size listed on those filters is a nominal size and not the size of the actual filter.

5. Our air filter's frame is made of sturdy aluminum and will not bend.

6. Take your time.  Get it right,  you'll never have to do it again, these air filters last a lifetime!