Orion 3517 Dew Zapper Pro 4-Channel Control Module The Orion Dew Zapper Pro is an advanced 12-volt DC dew prevention and elimination system which can power up to four heating bands to prevent dew accumulation on all your optics (heating bands sold separately) Microprocessor-controlled circuitry delivers pulse-width modulation for precise temperature control of up to four heating bands Each heater output has its own temperature control knob with adjustment from 0% to 100% so you can set each one to your preference Heating bands are power-efficient, drawing only 0.25 amps to 2.8 amps at maximum output (heating bands sold separately) Don't let dew dampen your spirits, or your telescope optics, get the made in the U.S.A. Orion Dew Zapper Pro today