1.Two Different Type Of Wireeach Pack Of Wire Hair Extension Comes With 2 Spare Wires. Fish Line Is Solid And Hard. And The Other Is A Transparent Elastic Wire, It Is More Flexibly And Soft.You Can Make Your Choice According To Your Need.2.Improved Way To Adjust The Length Of Wire. We Used To Adjust The Length Of Wire By Clipping The Wire, Which Is Irretrievable. Now, We Improve It With An Adjustable Hook. You Can Adjust The Wire By Changing The Place Of The Hook