Set monthly allowances for minutes, texts, and cellular data usage on any line on your T-Mobile account, or even block calling, texting, and data usage entirely for set periods of time during the day or night. You can also add up to 10 phone numbers on an "Always Allowed" list and 10 phone numbers on a "Not Allowed" list. "Always Allowed" phone numbers will allow messages and phone calls to go through regardless of any allowances or restrictions.
This add-on is intended to help parents manage their kids' cell phone usage.
Learn more here.