This .NET class wraps the AcDbMLeader::gsMarkType ObjectARX enum.

Public Enum GsMarkType
  ArrowMark = 1
  BlockMark = &H3a9c
  DoglegMark = &H2711
  LeaderLineMark = &H1389
  MTextMark = &H3a99
  MTextUnderLineMark = &H3a9a
  None = 0
  ToleranceMark = &H3a9b
End Enum

public enum GsMarkType {
  ArrowMark = 1,
  BlockMark = 0x3a9c,
  DoglegMark = 0x2711,
  LeaderLineMark = 0x1389,
  MTextMark = 0x3a99,
  MTextUnderLineMark = 0x3a9a,
  None = 0,
  ToleranceMark = 0x3a9b
}