Wrist-worn device clasp

A wrist-worn device clasp having a first side and a second side, configured to secure a strap, the wrist-worn device clasp comprising:

• a mechanical interlocking mechanism comprising a first mechanical part on said first side and a second mechanical part on said second side, said first mechanical part being configured to interlock with said second mechanical part by motion in a first plane to resist motion perpendicular to said first plane and inhibit a first securing part and a second securing part being separated by tension along said strap substantially perpendicular to said first plane when said first mechanical part and second mechanical part are engaged with each other;
• and
• a securing mechanism comprising said first securing part on said first side and said second securing part on said second side, wherein said first securing part comprises a first magnet located within a first central region of said first mechanical part, wherein said first central region is substantially parallel to said first plane and wherein said second securing part comprises a second magnet located within a second central region of said second mechanical part, wherein said second central region is substantially parallel to said first plane, and
• wherein said first magnet and said second magnet are configured, when magnetically engaged with each other by motion perpendicular to said first plane, to inhibit separation of said first mechanical part and said second mechanical part by motion parallel to said first plane.