The Axes list in the Position dialog box (Insert | Dimension | Position) 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
D1 = Diameter /Width of the first datum
D2 = Diameter /Width of the second datum
D3 = Diameter /Width of the third datum
DF = Diameter /Width of the feature
LF = Length of the feature if the feature is a slot
WF = Width of the feature if the feature is a slot
LD = Length of the datum if the datum is a slot
WD = Width of the datum if the datum is a slot
TP = Position tolerance and its associated deviation
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.