Unicel C-4637 Replacement Filter Cartridge for 37 Square Foot Rainbow， Waterway Plastics， Morgan Spas， Leisure Bay Spas， Custom Molded Products<div style="text-align: left;"><strong>[Product Information]</strong><br><ul><li>Diameter: 4 15/16-inch; length: 13 5/16-inch</li><li>Top end cap: open， 2-1/8-inch inner diameter; bottom end cap: open， 2-1/8-inch inner diameter</li><li>Pleat count: 158; filter media: 4-ounce reemay 2040; filter area: 37 square feet</li><li>Get more efficient filtration and better water clarity with Unicel filters</li><li>Longer time between cleanings; meets oem specifications</li></ul></div><img src="http://ecx.images-amazon.com/images/I/41nOw5vovvL.jpg" noproxy>