Quantities:500units per color per bottle,net weight:about 28g.Size:3.0mm(outer diameter)*1.6mm(inner diameter)*2.0mm(length). The silicone lined nano beads can protect your hair out of any hurt and can hold your own hair more tightly.prevent the stick hair extensions falling off from your head. The extensions will last several months, depending on how fast your own hair grows. Eventually, the micro rings will have to be removed, or moved up towards the scalp again. We use the excellent silicone pipe to make it. Being the most undetectable method of hair extensions installation and the smallest link attachment available in the market, with a size of only 3mm. NANO BEADS ARE AS SMALL AS A BALLPOINT PEN NIB - Our silicone lined nano beads are 90% smaller than regular hair extension application rings,.