diff --git a/docs/spec/04.00.00.conventions.md b/docs/spec/04.00.00.conventions.md
index f8d6670..8f898ab 100644
--- a/docs/spec/04.00.00.conventions.md
+++ b/docs/spec/04.00.00.conventions.md
@@ -49,6 +49,12 @@ byte.
 
 * varUI32 and varUI64 types must be decoded by the LEB128() function.
 
+* varUI32 can represent vaules in the range 0 to 2^32 - 1.
+  * E.g. 0x10000000 will be stored using 5 bytes.
+
+* varUI64 can represent vaules in the range 0 to 2^64 - 1.
+  * E.g. 0x100000000000000 will be stored using 9 bytes.
+
 
 ### General Conventions