The TK17 is the first Acebeam model with a single 18350 powered rechargeable battery. The TK17 is an ultra-compact EDC flashlight with outstanding performance. There are three different emitter options available for the TK17. The SAMSUNG LH351D, OSRAM KW CSLNM1.TG and the NICHIA 219C. The TK17 is powered by one 1100mAh 18350 Li-ion battery that emits powerful brightness with long runtime. The included 18350 battery can be recharged through a built-in Micro-USB port so no external charger is needed to charge the battery. The TK17 is constructed from durable high-strength and oxidation-resistant aluminum and paired with three LEDs and a TIR optic lens to provide a perfect medium to close-range illumination experience. The TK17 features five brightness levels plus a strobe. This exquisite flashlight is made with great attention to detail. The TK17 flashlight is a must-have for your daily life, outdoor activities, traveling, and on duty.