diff --git a/yaml/xyz/openbmc_project/Inventory/Item/Cable.interface.yaml b/yaml/xyz/openbmc_project/Inventory/Item/Cable.interface.yaml
index 486e56b..8d4a774 100644
--- a/yaml/xyz/openbmc_project/Inventory/Item/Cable.interface.yaml
+++ b/yaml/xyz/openbmc_project/Inventory/Item/Cable.interface.yaml
@@ -1,3 +1,10 @@
 description: >
     xyz.openbmc_project.Inventory.Item.Cable should be implemented on objects
     that represent a cable instance or a system cable instance.
+properties:
+    - name: Length
+      type: double
+      default: NaN
+      description: >
+          The length of the cable in meters.  The default value of NaN
+          represents a cable of unknown length.