US Gen3 Montero Cabin Air Filter
The search is over - these are the only cabin air filters I've ever found that actually fit US spec Gen3 Monteros without needing to cut or modify any part of the filter and that attach securely with 2 screws, one on each side.
These units feature activated charcoal for enhanced filtering of odor and harmful fumes.
Recommended service life: 10,000 miles regular use, 5,000 miles severe use (lots of dusty offroad trails)
Special Mitsubishi FB Group Pricing:
1 Filter: $20 shipped
2 Filters: $35 ($5 savings) shipped
NOTE - Your US Gen3 will need to be slightly modified to accept a cabin air filter. You just need to remove the lower glove box, remove one bolt holding a metal wire clamp that is in the way on the right side, and then cut out the rectangular filter opening in the blower box. The rectangle opening is already indented so all you have to do is follow the lines with a dremel tool or even a sharp utility knife. Then you just slide the cabin air filter in (Arrow pointing down) and secure with two screws into the existing holes (screws not included).