EZ Flex filter cartridge kit. Approximately 16 x 25. This original factory replacement kit is designed for people who have a pleated media air cleaner that uses cardboard framed filters presently. The kit enables you to replace that original filter with one of higher efficiency that takes up less space for shipping and storage and thereby costs substantially less to ship. Future filter replacements only require replacing the pleated media portion of this kit. This pleated media material is less expensive than the original and works better.