Dimensions: Length 2 15/16", Diameter 4 1/4", Openings: 1 7/8" Top & Bottom. Designed to fit ALL Intex PureSpa models including 28403E, 28407E, 28413E, 28421E, 28423E, 28425E, 28427E, 28439E, 28441E, 28443E, 28453E and 28481E, PureSpa Plus Model 28429E, 28431E. Note: All names are for compatbiblity purposes only. Superior Filtration: Meltbown technology allows for superior filtration over the standard pleated material used in most pool and spas, meltblown filters also keep the debris locked into the material, keeping your pool cleaner without the use of chemicals No More Cleaning: No more washing off the outside of the filter, metlblown filters last much longer than the standard pleated filter. It is also recyclable. 100% American Made and Sourced Melt blown filters are designed to hold a significant amount more dirt and particles than a pleated filter. Melt blown filters will also filter down to a much lower particle size than a pleated filter giving you a much cleaner pool without the use of much of the chemicals you would typically have to use.