The BT-Settl/CIFIST2011 grid was computed with the best physical ingredient of that time, it has a wide coverage of the parameter space.

The BT-Settl/CIFIST2011_2015 models include some physical refinement, but have a more restricted coverage of the parameter space.

BT refers to the water vapor line list by Barber, Tennyson et al. (2006). CIFIST2011 stands for the Caffau, Ludwig et al. (2011) solar abundance value.