The Corteco W0133-1940039 (linked to above by VetJazz) is activated charcoal even if it does cost more than the others. But, like I mentioned, it's mostly a gimmick due to there not being enough charcoal to last long enough to make much of a difference unless it's changed all the time. Before it was legal to grow the green herb, growers used to use activated charcoal filters to filter the EXAUST air from their grow rooms. My friend worked in a (legal) factory in Seattle that manufactured these charcoal filters. If I recall, they had around 20 pounds of charcoal in each filter, cost around $80 each (would be double that today) and needed replacing every couple of weeks when the plants were flowering. This was for a bedroom sized operation. But, if replaced regularly, they did remove most of the fragrance from the exhausted air which helped keep the rip-off bandits and law enforcement at bay.
My one concern with any non-OEM filter is that it not be overly restrictive. This can increase the load on your climate control fan and reduce airflow. But it's fairly inconvenient to measure this without specialized equipment.