Brand: Ochinai Kun 2; Size (approximately): Diameter 0.224 inches (5.7 mm); Height 0.177 inches (4.5 mm). Weight per item: 0.007 oz (0.22 g). Material: Surgical/medical grade stainless steel. Color: Silver. Made in Japan. Note: Earring catches that do not fall off.They come only in one size which can fit various post thickness 0.024 - 0.036 inch (0.62 - 0.92 mm).These earring catches are made in Japan and assembled one by one.They are also called "earring locks".