A plastic fastener for use in tagging an article of commerce. The fastener comprises an elongated filament having a first end and a second end. Disposed at the first end of the filament (63) is a transverse cross-bar (65) which is sized and shaped to be dispensed through an article of commerce using a tagger gun having a hollow slotted needle. Disposed at the second end of the filament is an enlarged paddle which is sized and shaped to prevent the filament (63) from being pulled completely through the article of commerce through which the cross-bar (65) had previously been inserted. The elongated filament is shaped to include an elongated central portion (69) having a longitudinal axis (69) and a first elongated rib. The first elongated rib extends along the length of the elongated central portion and serves to increase the cross-sectional surface area, and hence the tensile strength, of the elongated filament. The first elongated rib projects out from the elongated central portion of the filament at an angle perpendicular to the longitudinal axis (69) of the central portion. In another embodiment of the present invention, the plastic fastener includes a second elongated rib which is disposed on the opposite side of the elongated central portion from the first elongated rib.