diff --git a/Packet-structure.md b/Packet-structure.md
index 74e3e97..48e2aea 100644
--- a/Packet-structure.md
+++ b/Packet-structure.md
@@ -1 +1,2 @@
-Packet size: 1-2 bytes (2 byte packet size indicated by 0x80 bit being set, in which case size = (first byte - 1) * 256 + second byte)
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+* Packet size: 1-2 bytes (2 byte packet size indicated by 0x80 bit being set, in which case size = (first byte - 1) * 256 + second byte)
+* ObjID: Either 1 byte, or if byte is 0, then a string. 254 is a special destination called "CO"
\ No newline at end of file