A pressurised refill canister (5) containing a composition including a propellant. The canister has an outlet valve (20) having a stem (6) biased to a closed position by a first resilient member. The stem (6) has a maximum outer diameter of greater than 3mm. At the outlet end of the stem at least part of the wall of the stem extends inwardly from the outside diameter for at least 50% of the radius.
