Application: Silicone-lined Micro Links Rings for Hair Extension (No silding from human hair, a great helper for Hair Extension Installation.) Made of high quality material, which is safe to put on your hair and without damage to your hair. With very soft silicone lining, which allows you to install them to the head for maximum comfort to the client and undetectable. It holds human hair very tightly after pinched and it will not easily get slide when wearing. 2500pcs-5mm-Black, very practical. GOTDYA 2500pcs 5mm Black Extension Beads,Silicone Lined Micro Rings,MicroLink I Tip Weft Beads for Hair Tinsel and Feathers Extensions