diff --git a/specification/metrics/sdk.md b/specification/metrics/sdk.md
index f9e358e1542..e4365075022 100644
--- a/specification/metrics/sdk.md
+++ b/specification/metrics/sdk.md
@@ -179,6 +179,7 @@ are the inputs:
     matching zero or more characters.  If wildcards are not supported in general,
     OpenTelemetry SDKs MUST specifically recognize the single `*` wildcard
     as matching all instruments.
+  * The `unit` of the Instrument(s) (optional).
   * The `name` of the Meter (optional).
   * The `version` of the Meter (optional).
   * The `schema_url` of the Meter (optional).