*Description* 100% Brand new and high quality. Filter Cartridge (Twin Pack) contains two type I filer cartridges, which are compatible with Bestway 300/330 gal/h filter pump systems. When an above ground pool is in regular use you will soon notice the filter pump running less efficiently and water becoming dirtier. This is because the filter cartridge is clogged with dirt and debris. There are only so many times you can clean it before it stops filtering grime and producing clean, clear water. It's recommended that you change your filter cartridge at least every two weeks during periods of prolonged use. If you're unsure whether the Bestway Filter Cartridge (Twin Pack) is compatible with your pool pump you should refer to your pump manual.lso note that this filter cartridge is not for Lay-Z Spa. Filter cartridges provides a hassle-free cleaning and rinsing. Filter cartridge is an essential above ground pool accessory to keep the pool water in excellent condition throughout the swimming season. For best performance, it is advised to replace the filter cartridge once in every two weeks. Features Filter cartridge size I, 3.1 x 3.5 Inch Ensures that filter pump runs more efficiently Compatible with 300/330 gal/h (220-240 V) filter pumps Should be replaced every 2-3 weeks Insert card dimensions: Length: 18 cm, width: 16 cm Compatible Filter Pump: Designed for Filter Pump Model: CA / Compatible Pump: 58384-58387-58388E-58390E-58390-58389 Product Description Package includes 2 x Cartridges *Notice* 1. Manual measuring, please allow 1 ~ 2cm error,thank you. 2. Due to the difference between different monitors, the picture may not reflect the actual color of.