Obviously the cross-slit valve belongs to the duckbill valve family. It shares the same features and benefits. The main advantage over a regular duckbill valve is that it has a lot larger flow capacity when the 4 cuspids open up. On the other hand cross-slit valves have a non-tortuous, straight line flow path as well and therefore can be used in applications where instruments are pushed through the valve. Such as in a Trocar used for minimal invasive surgery procedures. Gas is prevented from venting out of the body cavity with either the instrument inserted or withdrawn from the Trocar.