Twenty teachers at Sierra Vista High School use Yondr pouches.
When students come in, they put their cell phones in the cases that magnetically lock.
At the end of class, the pouches open when they're swiped on the unlocking base.
"The engagement in the classroom went up," said Dr. John Anzalone, Sierra Vista's principal. "I actually had several students come up to me and say, 'Thank you because I haven't focused in class like this in years.'"
Debbie Simon, a Spanish teacher, says before the pouches, she was constantly stopping her class because of cell phone interruptions.
If there's an emergency, students can unlock their phones and step out of the room.
Anzalone also points out parents can still call the school if they need to reach their child, just like it was done in the days before smartphones.
This is the second year Sierra Vista has used Yondr pouches. Last year, only five teachers had them.
Anzalone hopes to expand the program to every classroom next year.