A unitary funnel which is injection-molded is used for dispensing a flowable product, such as a fuel additive, into a receptacle provided with a normally-closed capless fitment. The funnel includes an inlet portion for receiving the flowable product, an inserting end portion for insertion into the capless fitment and a body portion having a tapered hollow interior and extending between the inlet portion and the inserting end portion. The inserting end portion includes a skirt which is constructed and arranged for proper engagement with the normally-closed capless fitment so as to open that capless fitment and allow the flowable product to be dispensed into the receptacle.