CO2 Tuning Valve Designed for Polyurethane or Nylon tubing. Simple installation pneumatic push in connector. After installation, the direction of the tube can be changed freely. Elliptical release ring help to connect tube easily by manual, no special tools required. Outside (and Inside where applicable) hexagonal wrench tightening. This Quick fittings are only used for industrial automatic apparatus and can not be applied on any medicinal equipment. Upgrade your aquarium setup with the CO2 Tuning Valve – Order now and experience the difference!