A clasp is configured to permanently interlock around a flexible strip of material and includes first and second interlocking members. Each interlocking member includes a plurality of hooks and a corresponding plurality of recesses, where the recesses of one interlocking member receive the hooks of the other interlocking member to secure a band within the clasp between the interlocking members. The recesses can be completely internal to the clasp to prevent external tampering. Each of the interlocking members can include various protrusions and ribs that compress and secure the band within the clasp, so as to prevent movement of the band between the interlocking members when interlocked.
