The present invention is a pod for containing a particulate sensitive substrate and for providing pressure equalization between the exterior and an interior environment of the pod and for minimizing gaseous fluid flow inside adjacent to the particulate sensitive substrate. The pod comprises a primary pod, a diaphragm positioned in a cover, the diaphragm having a normal undeflected position, the diaphragm deflectable from the normal undeflected position. Preferably, the pod comprises a secondary pod disposed in the primary pod defining a second enclosure for containing the particulate sensitive substrate. The pod may comprise a filter attached to the pod and providing gaseous fluid communication between the exterior of the pod and the interior of the pod. The diaphragm is responsive to rapid pressure changes and the filter is responsive to slower pressure changes and allows the diaphragm to return to its normal undeflected position.