Size:5.0mm(outer diameter)*3.0mm(inner diameter)*3.0mm(length) Quantities:500units per color per bottle,net weight:about 40g. Color Available: #1 black, #3 dark brown, #5 brown, #6 beige blonde,#8 dark blond, #11 light brown,#13 light blonde.can match your hair perfectly. Silicone lined micro rings beads are used for (0.8g/1g)/strand I Tip stick feather hair extensions. Silicone beads with the soft silicone lined inside,do not damage to your own hair,the silicon pipe can hold the hair tightly prevent the extension from sliding. Silicone lined micro rings: thanks to the small size and light weight can be attached to your hair easily and invisible .