NEEWER USB 500mm lens heater with FPC, fast, even heating technology for DSLR camera lens telescope astrophotography, 3 temperature levels, prevents overvoltage/dew/mist/condensation, HW-30

["Improved Heating with FPC Technology"] This lightweight yet durable lens heater was designed with FPC (flexible printed circuits) technology, using polyimide films as insulators for reliable dielectric performance, and thermal foil as the heating element for improved heat conduction and higher heat transfer efficiency to quickly and evenly warm your lens. Note: The lens heater is bendable but cannot be folded. ["Effective Heating Length of 20"/500mm"] Eliminate dew, fog, and condensation with our specially crafted lens warmer when shooting in cold weather. For optimal performance and even heating, it is recommended to use on lenses or telescopes up to 20"/500mm in circumference and 160mm in diameter. ["Safe 5V 2A USB Power Supply"] Powered by any 5V 2A output USB power source via the 6-foot/1.8m USB cable, this lens heater features overheating/overvoltage protection for safe use. A controller offers 3 temperature levels (High: 125.6°F/52°C; Medium: 113°F/45°C; Low: 98.6°F/37°C) for different environments. ["Attachment via Velcro Strap"] Due to the flexibility and thinness of the FPC, the heater can be easily wrapped around your lens using the Velcro strap. Note: The heating area length is 20"/500mm, with a total length of 26"/650mm, including the Velcro strap. ["A Multifunctional Heating Device"] With a total length of 26"/650mm (including the attachment part), this multipurpose heating device can also keep your coffee cup warm in winter (use with caution). It can also be used on telescopes, riflescopes, etc.