Cap with locking function to prevent hose from escaping due to malfunctions or misoperation. Fits oval open rings. Installation Method: Align with the semi-circular part of the one-touch union open ring. Insert the open ring into place. Please insert firmly into place. Cannot be used with circular open rings or some large open rings. ■For 0.2 inch (6 mm) hoses ■ Quantity: 4 pieces