Kiwifotos USB Lens Dew Heater, Lens Warmer Strip with Temperature Regulator Condensation Prevention for Telescopes Camera DSLR Lens Telescope Eyepieces 80mm-110mm in Diameter

Good quality and cheap price

Does its job fine. Wish it would automatically come on when it gets power instead of me having to remember to turn it on.One thing to note that I think other reviewers touched on - you can't get around the max amperage draw by using a lower setting. High draws constant full power, and medium and low draw intermittent full power. If it can't draw full power it won't work.

Really good for late night astrophotographers

Press and hold the button to turn on. Seems to keep the dew off.

It's cold in Manitoba, this lens heater did the trick by being able to stay out longer.