A valve having a first housing including a first lumen extending therethrough and a first disk-facing surface, a second housing including a second lumen extending therethrough and a second disk-facing surface, where the second housing is coupled to the first housing so that the second disk-facing surface faces the first disk-facing surface. A flexible disk has at least a portion of an outer edge of the disk extending away from a plane of a central portion of the disk, the outer edge contacting the first disk-facing surface, the disk including a slit extending therethrough which, when acted upon by a fluid pressure of at least a threshold level opens to permit fluid flow between the first and second lumens and which, when acted upon by a fluid pressure less than the threshold level, prevents fluid flow between the first and second lumens.
