(CNN) -- One high school in the Bay Area of California is using a device developed by a San Francisco start-up to keep cell phones out of students' reach while class is in session.
The Yondr pouch locks away students' cell phones until the end of the school day. (Source: CNN)
It's called a Yondr pouch, and only teachers have the magnetic key necessary to release phones.
Every student at San Mateo High School now starts the day by putting their phone in one of the locking pouches, and it doesn't come out until school is dismissed.
School officials tested the program last year after noticing some kids spent too much time lost in their phones instead of learning or socializing.
It was so successful, they rolled it out to all 1,700 hundred students this year.
"I really think it's about being present and engaging in the adult that's trying to teach you, your peers that might be in your small group,” Assistant Principal Adam Gelb said.
Contrary to what you might think, many students say staying away from their phones while at school is a good thing.