Possible Clues:

• Custom brooch for a defensive back in the NFL?
• Certain fastener
• Diaper fastener
• The point of this device is not always apparent
• Loose ends in pinny I fasten - with this?
• One can't see the point of this device being used
• One's point is not usually clear
• Usually one cannot see the point of this fastener
• Edges to possibly fasten? I should be effective!
• Grenade release mechanism