The present application concerns a canister (10) for containing an active agent, such as a desiccant agent, an oxygen scavenger, or a scented agent and for allowing the active agent to interact with the environment of the canister (10), such as absorbing moisture or oxygen, when the canister is closed. The canister comprises a canister body (12) having a peripheral body wall (11) defining an upper opening (13) for inserting the active agent into the canister body (12), and a non-removable snap-on cap (14) cooperating with the canister body (12) so as to close the upper opening (13), the cap (14) comprising a peripheral skirt (C5). The peripheral body wall (11) comprises a step (B2) formed between a first portion (B5) of the peripheral body wall (11) located adjacent to the upper opening (13) and a second portion (B6) of the peripheral body wall (11) located beneath the first portion (B5). The first portion (B5) is at least partially thinner than the second portion (B6) so as to form the step (B2), wherein an inner shape of the peripheral skirt (C5) and an outer shape of the first portion (B5) of the peripheral body wall (11) are adapted to form a snap-on fit between the cap (14) and the canister body (12) wherein the cap (14) at least partially laterally surrounds the first portion (B5). According to the invention, a vertical extension of the peripheral skirt (C5) is smaller than a vertical extension of the first portion (B5) of the peripheral body wall (11) so as to form a gap (J8') between the step (B2) and the peripheral skirt (C5) when the cap (14) is snapped onto the canister body (12).
