Abstract: A canister includes a substantially cylindrical body having (i) a sidewall shell; (ii) a transition region; (iii) a dome portion extending from a convex annular portion to define at least a partially closed dome at one end of the body cylinder; (iv) and an opposing, open end of the cylindrical body; and a curved bottom member recessed within and sealed at a periphery thereof to the sidewall shell at the open end of the cylindrical body. An annular, exterior surface portion of the bottom member bears on an annular, exterior surface portion of the transition region thereby forming a space between and within the annular exterior surface portion of the bottom member and an exterior surface of the dome portion when the canister is stacked on a substantially identical canister.