The 2nd Generation Nest Learning Thermostat has a new, slimmer design, is enclosed by a solid stainless steel ring, and works with 95% of low voltage systems. The Nest Learning Thermostat learns what temperatures you like, turns itself down when you"re away and can be controlled from anywhere over Wi-Fi. By programming itself, the Nest thermostat can save up to 20% on your heating and cooling bill. You just have to teach it well.