Built to deliver a powerful beam of light, the TK21 features a new reflector shape that provides a beam pattern with both strong spill and spot capabilities. Powered by either two CR123 batteries or a single rechargeable 18650 (Li-ion) battery, the TK21 can offer both high light output of up 468 lumens and long runtimes of up to 200 hours. In addition, the lithium batteries are frost resistant, enabling the flashlight to operate even in frigid conditions. The TK21 is designed with an easy-to-use side mounted pushbutton that allows the user to cycle through its four brightness levels quickly. Constructed with durable aircraft-grade aluminum that is coated with a premium type III hard-anodized, anti-abrasive finish and waterproof to IPX-8 standard, the TK21 can stand up to virtually any conditions. Thanks to digitally regulated circuitry as well as a toughened ultra-clear glass lens with an anti-reflective coating, the TK21 provides a consistent and steady beam. While the TK 21 is suitable for any outdoors use from search and rescue to general navigation, the TK21 is specially outfitted with hunting-specific features including support for a gun mount, a remote pressure switch, an anti-roll, slip-resistant tactical grip ring, and dual-recoil absorbing springs for superior impact resistance. Additional user-friendly details include a side dimmer button, a rapid and regular strobe mode, a momentary-on switch, and reverse polarity protection. The TK21 comes with a lanyard and holster and carries a limited lifetime repair warranty from Fenix.