Made of clear, Non-Toxic PVC ยจ Colour coded kit for ease of use and delivery of variable concentrations of oxygen. Two Color coded diluters for seven concentrations: Green diluter for 24%, 26%, 28%, 30% White diluter for 35%, 40%, 50% Six Color coded diluters for six concentrations: 24%, 28%, 31%, 35%, 40%, 50% Adjustable nose clip. Adaptor for high humidity. With 2m anti-crush tube.