Facebook co-founder Mark Zuckerberg is showing off a new invention he created to help his wife sleep better.
"The Sleep Box" emits a dim light between the hours of six and seven in the morning.
This allows his wife to know whether it's time to wake up or continue sleeping.
Zuckerberg says building a device to help his wife sleep better is one of the best ways he can think of to show his love and gratitude.
The couple got married in 2012 and have two children together.