Astrozap Dew Heater - 1-1/4 Inch Eyepieces & 50mm Finder Scope - SKU# AZ-701. Dew heater specs: 5" in length, 2.5 Watts @ 12 Volts, 0.21 Amps. This product requires the use of a simple D/C adapter (AZ-719) or dual channel controller (AZ-720) to be powered.Use of a dew controller other than Astrozap brand can cause damage and void the warranty.