Tier1 13.31 in. x 5 in. 50 sq. ft. Pool and Spa Filter Cartridge for PRB50-IN, FC-2390, C-4950 TIER1-PAS-1447 - The Home Depot
✓Lifesmart Spa Filter 5.5" Top x 10"Tall Male Thread 1.75" Fits models LS-100, LS-200, LS-350, LS-400, LS-600
Amazon.com: Cosyspa Hot Tub Filter | Spa Pool Standard & Screw in Replacement Cleaner Cartridges | Compatible with All Inflatable Hot Tubs [Pack of 1/6/12] (Screw in, Pack of 6) : Patio, Lawn & Garden
Hot Tub C4326 Filter Prb25in Spa Filters Beachcomber Arctic Spas Reemay - Spa Tubs - AliExpress
Bestway Bestway Type Vi Spa Filter Cartridge For Lay-z-spa Twin Pack 58323 : Target
Dimension One Spas Hot Tub Filter 1561-00 - Spa Place Inc.