An evaporative emission control canister for an automotive vehicle includes a canister body and a bracket for attaching the body to a structural member of a vehicle. A number of fastener sets attach the bracket to the canister body, with each of the fastener sets including a closed-end hollow core boss having a generally cylindrical wall of uniform thickness and a number of buttresses applied to an outer surface of the generally cylindrical wall. The buttresses have the same uniform thickness as the generally cylindrical wall and are molded along with the cylindrical wall as one piece with an inner portion of the canister body.