Constructed from simple materials like sheet plastic and PVC pipe, these small wind turbines are perfect for someone who wants to experiment with wind energy or for a small cabin system. Includes 20 feet of wire, ring terminals to go to your 12V battery and everything else you need to build your turbine. Starts charging at a very low wind speed, 3-4 mph. Blocking diode is installed and no charge controller is required. NOTE: Maximum wind speed for this turbine is 20 mph. These simple turbines do not have advanced speed control mechanisms, and can be damaged by higher wind speeds. Unit is designed to sit on 1" electrical EMT pipe (available at hardware and home improvement stores) for your pole (not included). Battery is required, min. of 32 amp-hr AGM. Complete instructions included. Specifications: Blade length: 12"; Overall length: 25"; Output max. 2.25 amps @ max. 22V. Typical output is less than 1 amp. Optimum wind speed: 15 mph; Max. wind speed: 20 mph.