A vaporization capsule including a liquid active agent absorbed in or adsorbed to a substrate, which may be operated so as to vaporize the liquid active agent. The vaporization capsule includes a capsule body defining a first volume and a second volume. A first cover sealingly engages the capsule body at a first end thereof. The first cover includes an exterior perimeter, an interior wall including a hollow defined between the exterior perimeter and the interior wall portion, and at least one indentation disposed in the interior wall portion, fluidly connecting the first volume and the second volume via the hollow.