The Lark Original and Lark Pro are devices which monitor sleep patterns, gently nudge users awake, and offer personalized advice on how to improve sleep patterns. Lark CEO Julia Lu told TechCrunch the company has sold “tens of thousands” of its devices, with 73 percent of users purportedly experiencing improvement after using Lark Pro for just one month. The company has now officially launched a daytime compliment to their sleep monitor, the Larklife, which shares many features with leading activity monitors like Nike Fuelband.