Nest's Temperature Sensor is now available for $39

You can get one from Nest's website or the Google Store.

Don't worry if you missed out on pre-ordering Nest's Temperature Sensor last month -- it's now available for purchase, and you can even get it straight from the company's website or from the Google Store. The puck-shaped device works in tandem with Nest's latest Learning Thermostat or its simpler and more affordable Thermostat E. In fact, you can get one bundled with either temperature regulator to save $20 or $10, respectively, if you don't have the company's thermostats yet.

The Temperature Sensor works by monitoring how cold or how hot a specific location in your house is. Its thermostat companion can then make sure that room stays at the temperature you specified -- like say, if you want your bedroom colder than the baby's room or your living room a bit warmer than everywhere else -- for max comfort. It sounds especially useful if you have a big house, which is most likely why Nest is offering a 3-pack bundle price for $99. You can still get just one sensor for $39, though, if you'd still like to make sure you don't get too hot or too cold in your apartment.