T-Mobile and AT&T say US regulators should drop a plan to require unlocking of phones within 60 days of activation, claiming that locking phones to a carrier’s network makes it possible to provide cheaper handsets to consumers. “If the Commission mandates a uniform unlocking policy, it is consumers—not providers—who stand to lose the most,” T-Mobile alleged in an October 17 filing with the Federal Communications Commission.

The proposed rule has support from consumer advocacy groups who say it will give users more choice and lower their costs. T-Mobile has been criticized for locking phones for up to a year, which makes it impossible to use a phone on a rival’s network. T-Mobile claims that with a 60-day unlocking rule, “consumers risk losing access to the benefits of free or heavily subsidized handsets because the proposal would force providers to reduce the line-up of their most compelling handset offers.”