This is a component of an in-floor cleaning system designed for swimming pools. Specifically, it's the collar that houses the pop-up cleaning jet. Here's a breakdown of its features and purpose:

• Part of the Q360 System: This collar is designed to work with Blue Square's Q360 in-floor cleaning system. This system uses strategically placed jets that pop up from the pool floor to sweep away debris.  
• Houses the Cleaning Jet: The collar is the housing that holds the actual water jet. It ensures the jet is securely mounted and allows it to rotate.  
• 360-degree Rotation: The "Q360" name indicates that the jet within this collar rotates a full 360 degrees. This ensures thorough cleaning coverage of the pool floor and steps.
• Pop-up Design: The jet is designed to pop up when in use and retract flush with the pool floor when not in use, creating a seamless look and preventing tripping hazards.
• White Color: The "WT" in the product code indicates that this collar is white. This allows it to blend in with most pool finishes.
• Replacement Part: This product is likely a replacement part for existing Q360 systems. Over time, these collars or jets may wear out and need to be replaced.

In summary, the Blue Square Heads & Collars Q360 Collar (11400WT) is a crucial component of an in-floor pool cleaning system. It houses and supports the rotating cleaning jet, ensuring efficient and comprehensive debris removal from your pool.