The Keratin Bond method uses keratin resin to fit hair into molded bonds by hand. This method is discreet, comfortable and extremely versatile. The bond method lasts up to three months! Designed for application with heat clamp. For more information on installing Keratin Tip extensions, get certified in our Keratin Masterclass! 18-20g, 20 pieces, Keratin Flat Tip Hair, 18 and 22 Double Drawn5 Inch Root