Abstract: A fastener includes an elongated shaft having a head at the end, the head comprising a lock fin extending radially outward from the shaft. The head includes an engagement cavity. The fastener further includes a cap having an engagement protrusion for insertion into the engagement cavity of the cap such that rotation of the cap causes corresponding rotation of the head, the cap further comprising a contact portion having a plurality of radially outward facing planar surfaces. The fastener further includes a rotation resisting element having inward facing planar surfaces that fit with the radially outward facing planar surfaces of the contact portion, the rotation resisting element further including an interference feature extending radially outward, the rotation resisting element being resilient so as to allow but resist rotation of the cap with respect to the rotation resisting element.