What is the difference between 661024 and 661024R

this filter features a deep-pleated design that maximizes surface area

Operating on a standard 120V AC 60Hz electrical supply

and 581P models

Reliable Motor Cooling: Suction gas-cooled motor design ensures thermal stability even during high-load cycles in ambient-intensive environments

York S1-FM501 Filter R-134A What is the difference betweenThe York S1 FM501 is a high efficiency deep pleat media filter designed specifically for 5 inch filter cabinets in residential HVAC systems. Engineered as a direct replacement for S1 MAC11202506 and S1 LFMA2025 models, this filter features a MERV 11 rating, providing a significant upgrade over standard pleated filters by capturing a broader spectrum of airborne contaminants, including dust, pollen, and pet dander. The low pressure drop design ensures