A New Jersey high school has discovered a simple—and pretty obvious—solution to widespread tardiness: If you want the student to show up on time, threaten their phone privileges.

Administrators at West Side High School in Newark have implemented a new tactic that requires late students to hand over their phones so it can be shut off and placed in a plastic pouch. ABC 7 reports the soft container is locked with a magnet similar to those used at clothing retailers. The student is then allowed to carry the pouch throughout the day. Once school ends, they must take it to the school’s vice principle, who will unlock the pouch with a special device.

According to NJ.com, the school used to confiscate cell phones as a form of punishment; however, officials stopped because it became a liability problem. (Students could claim their phones were returned damaged, or administrators could accidently lose them.)

Several students have said the new policy not only motivates them to show up on time, but it has actually helped them concentrate more in class.

“I think not having it (the cellphone) really helped me,” West Side senior Raymond Jongbo told NJ.com. “I did all of my work much faster. I could focus in class and listen to the teacher.”

Though he definitely saw the benefits of having zero access to his phone, Jongbo insisted he was never going to be late again.

ABC 7 points out that two-thirds of West Side students are given a phone or tablet by the school as way to help balance their responsibilities at home.

A lot of the kids come from families with very few resources. Many students are taking care of small kids. Some even have their own children, or care for elderly grandparents so they may face many responsibilities other kids never dream of, before 8 o'clock in the morning.

Officials said the seven-week pilot program has effectively curbed tardiness and that surrounding schools have taken notice.