This product is suitable for all kinds of wooden doors, plastic doors, aluminum doors, etc. Located in the upper end of the hydraulic hinge, clockwise knob closing strength becomes larger, counterclockwise becomes smaller. Clockwise knob into 15mm for the best closing strength. Afternoon sunshine diffuses through the eaves, touch it, it becomes spring. Size: As shown Package: 5pcs, Manufacturer: Shun Yingtong