Tri-Mer Corp. Tri-Flow is a filtration concept delivering HEPA-level performance with a MERV 16 rating. Tri-Flow Compact filters are a higher-performing alternative to bag, cartridge and pocket filters, which are typically MERV 10-13. They have a small footprint, and exceptionally large filter surface area: Tri-Flow Compact filters provide 2-3 times more filtration compared to similarly dimensioned bag (pocket) filters. The system uses seven proprietary media tailored to the application, including PMF (polyester with nanofiber overlay) and PTFE for high humidity applications. Media is pleated and bonded for dimensional stability.