【Effective 20 " / 500mm Heater Length】Eliminate fog and condensation with our specially crafted lens warmer for cold weather photography Suitable for lenses or telescopes up to 18.7 " / 475mm circumference and 150mm diameter 【USB】Conveniently powered by USB, our lens heater can be plugged into various power sources offering a USB 5V 2A output The 4.9ft / 1.5m long cable allows for flexible indoor and outdoor use 【Versatile Usage】Not only suitable for lenses and telescopes, but also serves as a multipurpose heater Keep your cup warm in winter or use it to warm your wrist, elbow, and ankle when feeling chilly 【Improve Your Photography Experience】With our lens heater, you can clear images even in chilly weather Say goodbye to misty images caused by foggy lenses and enjoy an photography 【Ideal for Photography Enthusiasts】Designed for photographers and outdoor enthusiasts, this lens heater provides a solution to fog on lenses during photo claps in cold weather conditions