Catch Silicone x K18 YG I purchased these, but I didn't use them. Please confirm the post size of your earrings before purchasing. Compatible with earrings with a K18 post thickness of 0.5mm to 0.7mm. Double-lock catch The silicone double-lock catch has metal inside the silicone. Due to the structure, if you don't insert the earring post straight, the metal part may come out when you remove it. When attaching, insert the earring post slowly and straight, being careful.