The blue Filter Adapter from Fenix is easy to attach and remove, and requires no modification to your flashlight. The filtered light protects night-adjusted vision, and blue light also highlights blood-trails for hunters who are tracking their game. Made of PC2805 polycarbonate, it is temperature and impact resistant. This filter is compatible with Fenix PD35, PD12, and UC40 flashlights. It comes ready-to-use in clamshell packaging.