diff --git a/src/schema/objects/enums.yaml b/src/schema/objects/enums.yaml
index 16b2e6c618..ba6d22f8e4 100644
--- a/src/schema/objects/enums.yaml
+++ b/src/schema/objects/enums.yaml
@@ -322,6 +322,22 @@ ChietiItab:
   display_name: Chieti ITAB
   description: |
     RAS orientation and the origin between the ears.
+calibration:
+  value: calibration
+  display_name: calibration
+  description: |
+    The fine-calibration file, is produced by the MaxFilter software and the work of
+    Neuromag/Elekta/MEGIN engineers during maintenance of the MEG acquisition system.
+    It is specific to the site of recording and may change in the process of regular system maintenance.
+    it is usually shared with a crosstalk file.
+crosstalk:
+  value: crosstalk
+  display_name: crosstalk
+  description: |
+    The crosstalk file, is produced by the MaxFilter software and the work of
+    Neuromag/Elekta/MEGIN engineers during maintenance of the MEG acquisition system.
+    It is specific to the site of recording and may change in the process of regular system maintenance.
+    it is usually shared with a fine-calibration file.
 individual:
   value: individual
   display_name: individual
diff --git a/src/schema/rules/files/raw/meg.yaml b/src/schema/rules/files/raw/meg.yaml
index 4bf7a42549..a25ed56646 100644
--- a/src/schema/rules/files/raw/meg.yaml
+++ b/src/schema/rules/files/raw/meg.yaml
@@ -39,9 +39,8 @@ calibration:
     session: optional
     acquisition:
       level: required
-      # TODO: Add definitions for these values.
       enum:
-        - calibration
+        - $ref: objects.enums.calibration.value
 
 crosstalk:
   suffixes:
@@ -55,9 +54,8 @@ crosstalk:
     session: optional
     acquisition:
       level: required
-      # TODO: Add definitions for these values.
       enum:
-        - crosstalk
+        - $ref: objects.enums.crosstalk.value
 
 headshape:
   suffixes: