1413 Aprilaire Upgrade Kit for Model 2400 Air CleanersGenuine Aprilaire 1413 Upgrade Kit High Performance Upgrade for Aprilaire Space Gard Models 2400 and 2140 This upgrade improves the efficiency of Air Cleaners. The upgrade kit comes with one MERV 13 rated filter (Part No. # 413) which is considered to be a 65% improvement. MERV 11 rated filter (Model No. 410) is also compatible but not included in 1413 Upgrade Kit Includes: MERV 13 Rated Filter, metal frame base, supports Frame simply snaps together