Lash extensions includes three typle: synthetic, silk and mink. They have kinds of sizes and shapes. Lash extensions are usually applied by a technician in a beauty salon, using tweezers and a specially formulated, semi-permanent glue. The procedure can take as long as two hours, and your eyes should remain closed for the duration of the application. The faux lashes typically last three to four weeks, falling off as your natural lashes shed.