When it comes to "Carbon Filters" the only task is to effectively remove hot, humid air and any airborne volatile organic compounds from the grow space. One filter manufacturer does it better than all the rest, Phresh. Pro 4/8 Carbon allows for unrivaled airflow and odour removal.
We stock the "Skinny" - Lower cost but still filled with RC-4/8 Carbon and a very effective filter. Suitable for 9-12 month of use (based on normal atmospherics) and as the name suggests a little smaller than the Phresh Exhaust Filter.
Our main extractor fan filters are the Phresh Exhaust Filters, packed with more of the higher grade Pro 4/8 carbon for exceptional air flow and potentially 2 years of use.
Both are great filters and came out top in HydroMag's Carbon Filter Comparison.