A sliding window has panels (called sashes) that move sideways on tracks using rollers instead of opening inward or outward. This saves space and allows wide ventilation.

A 3-track frame means the window frame has three parallel rails. Typical setup:
• 3 sliding glass panels
• Each panel moves on a separate track
• Panels slide left or right

Benefits:
• Wider opening than 2-track windows
• Better airflow and panoramic view
• Suitable for large openings like halls or balconies.