The Axes drop-down list provides you with a list of available axes, to which you can apply Plus and / or Minus tolerances. The list contains the following:
All - All the axes and options displayed in the drop down list
X - X axis value
Y - Y axis value
Z - Z axis value
D - Diameter
R - Radius (half of Diameter)
A - Angle (for cones)
L - Length (used for cylinder, slots, cones, and ellipses)
H - Height
PR - Polar Radius
PA - Polar Angle
T - Error along the approach vector (for points on curved surfaces)
RT - Deviation along the report vector
S - Deviation along the surface vector
RS - Deviation along the surface report
PD - Diameter of a circle (perpendicular to the pin vector)
FORM - The integrated form dimension for the feature.
For a circle or cylinder feature, this is the Roundness (RN) dimension.
For a plane feature this is the Flatness (FL) dimension.
For a line feature this is the Straightness (ST) dimension.