These flat top crescent moons screw into 16G post with standard 0.9mm threading. (They fit our SI-LAB24 or TI-LAB24 16G posts.) Manufactured as one sturdy piece from ASTM F136 titanium, so they can be anodized a creative color - how about a blue moon? Your choice in mini 3-4mm moon, suitable for nostril, or the larger 5mm size more appropriate for helix or earlobe.
