Abstract: A snap fastener for securing two structural components to each other has a fastener section with a head and stem with at least one axial slot (6, 7) in the stem opposite the head to form snap-on members (3A, 3B, . . . ) spaced by the slot (6, 7) in the stem (S). A washer fits over the snap-on members around the stem when the snap-on members are pressed toward each other. The locking members have shoulders (4) that engage the washer and form the snap-on connection. A locking bail (12) fits with a central portion into the slot so that the snap-on members cannot be pressed together anymore, thereby preventing the unlocking. The locking bail has at least one locking hook (15 or 16) that engages the washer so that the central portion (13) of the locking bail (12) cannot escape out of the slot. The locking hook can be intentionally disengaged against its elasticity for removing the snap fastener.