Enlarge (credit: Getty Images | Linda Jo Heilman)

AT&T is the latest US mobile carrier to announce a new “unlimited” data offer. Starting tomorrow, AT&T will sell unlimited data for $100 a month “to all consumer and business postpaid AT&T wireless customers,” the company said in a press release. Previously, AT&T only offered unlimited data to mobile customers who also subscribed to DirecTV or U-verse TV.

The single-line price is higher than AT&T’s competitors are charging, and the plan has some limits despite its name. Unlimited data can only be used on the mobile device itself because the plan includes no tethering, an AT&T spokesperson confirmed to Ars. Customers who want to use their phones as hotspots will thus have to buy one of AT&T’s capped plans.

By default, the new unlimited plan also has video quality limits. The announcement says that the “plan includes Stream Saver,” a reference to a system that reduces video quality to about 480p resolution. Stream Saver was originally intended to help customers use less data on plans with data caps, but in this case it’s being applied to customers who don’t have strict data caps.