Trane BAYFTFREXM (4-Pack) – Perfect Fit 5″ Expandable Replacement Air Filter This is an authentic and brand new Trane BAYFTFREXM (4-Pack) – Perfect Fit 5″ Expandable Replacement Air Filter Trane recommends this filter be replaced every 6-12 months for maximum efficiency and effectiveness. Much of this depends on the condition of the environment it is servicing. Specifications: – MERV Rating: 8 – Filter Life: Up to 12 Months – Nominal Size: 25″ x 5″ – Requires: Retrofit Frame Kit Features: – Easy Sliding Cartridge for Quick Replacement – Evenly Spaced Pleats Capture Maximum Particles – Keeps Your HVAC System Operating at Peak Performance