The FA10995_LISA2-M-PIN-XP is a 9.9mm round Medium Lens made of optical grade PMMA (Polymethylmethacrylate) with high UV and temperature resistance (105°C/220°F) and lens holder molded of high quality black PC (polycarbonate). It is specially designed for use with for Cree's XP series of LEDs. The fastening of holden to PCB with appropriate adhesive.