diff --git a/LXMF/LXMF.py b/LXMF/LXMF.py
index 5c73f56..c128652 100644
--- a/LXMF/LXMF.py
+++ b/LXMF/LXMF.py
@@ -12,7 +12,7 @@ FIELD_ICON_APPEARANCE  = 0x04
 FIELD_FILE_ATTACHMENTS = 0x05
 FIELD_IMAGE            = 0x06
 FIELD_AUDIO            = 0x07
-FIELD_THREAD           = 0x08
+FIELD_THREAD           = 0x08 # Bytes, full thread ID hash
 FIELD_COMMANDS         = 0x09
 FIELD_RESULTS          = 0x0A
 FIELD_GROUP            = 0x0B