The S20 portable solar energizer powers up to 12 miles / 40 acres of single wire fence with no vegetation and boasts several solar technology improvements that make it ideal for temporary grazing applications, livestock and pet containment. The S20 is quick and easy to install and convenient to transport. This robust and highly portable unit makes a great alternative to battery-powered systems. Works for up to 3 weeks without sun and is capable to power through the harshest winters.