Abstract: A closure is provided for canisters, in particular canisters having a relatively large mouth or opening, and designed for keeping foodstuffs in the kitchen. The canister opening is defined by a sidewall, and the closure comprises a skirt that is radially expandable in a controlled manner for clamping inside of the sidewall, or releasing the sidewall, to seal or open the canister opening. For the controlled expansion or contraction of the skirt of the closure, the skirt is flexibly connected to a convex bottom. The bottom includes a conical, relatively rigid intermediate ring panel sloping downwardly toward the interior of the canister from the skirt, and a rigid central panel circumferentially hinged to the intermediate panel and axially movable in a controlled manner for varying the slope of the annular intermediate panel, thus varying the effective diameter of the skirt.