Product: Water Oil Filtration Hose Coupling Key benefits Provides a reliable, leak-resistant coupling for small-diameter silicone tubing used in water, oil and air/oxygen filtration systems. Transparent body lets you visually inspect flow and detect blockages or bubbles without disassembly. Solid, thick construction and careful workmanship reduce the risk of cracking or deformation during installation and use. Size and compatibility 4MM: fits silicone tubing with 3–4 mm internal diameter 6MM: fits silicone tubing with 5–6 mm internal diameter 8MM: fits silicone tubing with 7–8 mm internal diameter 10MM: fits silicone tubing with 9–10 mm internal diameter Function and performance Designed to couple silicone hose sections while maintaining filtration function for water, oil, and air/oxygen lines. Clear, precise fit for compatible tube internal diameters ensures a secure connection and consistent flow. Thick, well-finished construction improves mechanical stability under typical operating conditions. Practical features Transparent design for quick visual checks of flow, sediment or air in the line. Simple push-fit installation for fast assembly and maintenance. Workmanship and thicker walls improve handling and resistance to routine stresses. Typical applications Small water filtration and pump connections in home or lab setups. Oil return or transfer lines on small engines, pumps or machinery where filtration and secure coupling are required. Air or oxygen tubing for aquarium aeration systems, lab equipment, or other low-pressure gas lines. Order note Select the coupling size that matches the internal diameter of your silicone tubing (see sizes above).