This is a set of four replacement cartridge filters manufactured by Unicel, designed to be compatible with specific Hayward pool filter models. Here's a breakdown:  

• Unicel Brand: Unicel is a reputable manufacturer of aftermarket pool and spa filter cartridges. They are known for producing high-quality alternatives to OEM (original equipment manufacturer) filters.  
• Hayward Compatibility: These cartridges are specifically designed to be compatible replacements for Hayward C4025 and C4030 filter models.  
• Set of 4: This product includes four individual filter cartridges, meaning you'll have a complete replacement set for your filter housing.  
• C-7488-4 Model Number: This is the Unicel model number, which helps identify the specific cartridges and ensures compatibility.
• Cartridge Filters: Cartridge filters work by trapping debris in the pleated filter media as water passes through.  
• Purpose: These cartridges are designed to remove dirt, debris, and other impurities from pool water, ensuring clean and clear water.  
• Replacement Filters: These are replacement filters, designed to replace old or worn-out cartridges in Hayward filter housings.  
• Benefits:
  • Provides efficient filtration.
  • Offers a cost-effective alternative to OEM filters.  
  • Easy to install and clean.

In summary: The Unicel Hayward C4025/C4030 Set of 4 (C-7488-4) is a set of four quality aftermarket replacement filter cartridges designed to keep your Hayward pool filter operating efficiently. They offer a good value and are designed to provide clear pool water.