This Dew Zapper Heating Band for 1.25" eyepieces and 30mm finder scopes is part of the larger Dew Zapper Pro 4-Channel Dew Prevention System. The required control module is sold separately. With Dew Zapper Pro you'll never again have to quit an observing or imaging session because dew clouded up your optics. Our advanced dew prevention system powers up to four individual heating bands independently. So you can keep all of your optics -- main telescope, finder scope, guide scope, eyepieces, or other optical accessories -- bone dry in high humidity or dew-prone weather. Five different heating band sizes are available. The heating bands (sold separately) are highly power efficient, drawing between 0.25 amps and 2.5 amps depending on the model, at maximum output. A 10-amp fuse in the control module prevents any mishaps from electrical surges or reversed polarity. And unlike competing dew-prevention systems, the Dew Zapper Pro's heating bands have right-angle cable connections to reduce cable strain and provide a tighter fit. Hook-and-loop fasteners hold the bands snugly around your instrument and accessories. Each heating band comes with a 6 foot long cable that plugs into the control module via an RCA-type connector. Removable caps are included to protect any unused ports from exposure to the elements. The control module also has an auxiliary 12-volt port, which allows you to power any 12-volt accessory directly from the module.