A strip includes a number of triangular holes each formed by a triangular peripheral wall for engaging with fasteners and for decreasing the contact area between the strip and the fasteners. The triangular peripheral walls each includes three surfaces each having a slit for increasing the resilience of the triangular peripheral walls and for allowing the triangular peripheral walls to resiliently supporting the fasteners in place and for allowing the fasteners to be easily disengaged from the strip when the fasteners are punched relative to the strip.