14K gold fill click-locking jump rings; Quality made click and lock super strong open jump rings.
To avoid marring the metal, two pairs of nylon jaw pliers are recommended.
How to open a click-lock Jump Ring:
Twist the jump ring open so that one end of the ring moves upwards and the end moves downwards.
Attached you rings, chain etc..
How to close a Click & Lock Jump Ring:
Moving in the opposite direction as before, twist the jump ring again, the two ends of the ring should pass each other. While applying pressure inward, twist the jump ring closed so the two ends of the ring touch each other, you should hear a click sound. This indicates the locking mechanism has worked. Wiggle the right side of the jump ring against the left side so the ring is properly aligned. Your jump ring is now securely closed.