This is a twist lock clasp — typically used for handbags, purses, briefcases, leather accessories, and sometimes even small boxes.

• The triangular part is the rotating mechanism.
• You turn (or twist) the small knob in the middle to lock or unlock the bag flap.
• It’s purely a mechanical closure — no key needed — and it’s designed for style and easy access.

The installation usually involves:

• Cutting a slot or hole in the leather/fabric,
• Inserting the lock through,
• Securing it with screws, prongs, or a backing plate.