Abstract: The present invention comprises a fastener including a rigid fastener body formed of two sections attached together and shaped so as to be insertable into a hole in a mat. The body being formed so that the fastener body is not rotatable when fitted into the hole. A flange extends at the head of the body. The fastener body can be used to secure mats one to another by fitting within aligned holes of overlapping mats simultaneously. A rigid locking rod is fit within a longitudinal bore within the fastener body, the rod having an enlarged head section, a longitudinal shaft midbody section and a foot section. The rod is in contact with the bore, but can be rotated upon the application of torque to the rod relative to the body to position a flanged end of the locking rod to either be extended out to engage against the mat about the hole or to be recessed. The flanged end of the body and the extended flanged end of the rod lock the mats in together.