diff --git a/doc/Developing/os/Health-Information.md b/doc/Developing/os/Health-Information.md
index bac139aa40..cfe38d2ebf 100644
--- a/doc/Developing/os/Health-Information.md
+++ b/doc/Developing/os/Health-Information.md
@@ -73,7 +73,7 @@ The only sensor we have defined here is airflow. The available options are as fo
 
   - `oid` (required): This is the name of the table you want to do the snmp walk on.
   - `value` (optional): This is the key within the table that contains the value. If not provided will use `oid`
-  - `num_oid` (required): This is the numerical OID that contains `value`. This should always be without the appended `index`.
+  - `num_oid` (required): This is the numerical OID that contains `value`. This should always include `{{ $index }}`.  snmptranslate -On can help figure out the number
   - `divisor` (optional): This is the divisor to use against the returned `value`.
   - `multiplier` (optional): This is the multiplier to use against the returned `value`.
   - `low_limit` (optional): This is the critical low threshold that `value` should be (used in alerting). If an OID is specified then divisor / multiplier are used.