Standard Grade Furnace Filter - 4 Pack - Efficient and Reliable Protection Product Overview: Protect your heating and air conditioning equipment with our reliable standard grade furnace filter, trusted around the world for over 50 years. Designed with continuous filament spun glass, this filter ensures peak performance and energy efficiency for your HVAC system. Now available in a convenient 4-pack. Key Features: Optimal Protection: Safeguards your heating and cooling equipment without causing additional strain. Efficient Storage: The nested construction design allows for convenient and space-saving storage. Long-Lasting Performance: Each filter is effective for up to 30 days, providing consistent protection and efficiency. Safety Certified: Rated UL Class 2 for added safety assurance. Convenient 4-Pack: Each pack contains 4 filters, ensuring you always have a replacement ready. Usage: For best results and to maintain peak equipment performance, replace the filter every month.