The LT317AT are 3-terminal positive adjustable voltage regulators which offer improved performance over earlier devices. A major feature of the LT317AT is the output voltage tolerance is guaranteed at a maximum of ±1%, allowing an overall power supply tolerance to be better than 3% using inexpensive 1% resistors. Line and load regulation performance has been improved as well. Additionally, the LT317AT reference voltage is guaranteed not to exceed 2% when operating over the full load, line and power dissipation conditions.
See the spec sheet HERE