diff --git a/standard_schema/prerelease/HED8.4.0.mediawiki b/standard_schema/prerelease/HED8.4.0.mediawiki
index 9b96b51..74548fb 100644
--- a/standard_schema/prerelease/HED8.4.0.mediawiki
+++ b/standard_schema/prerelease/HED8.4.0.mediawiki
@@ -512,7 +512,7 @@ Each term in this vocabulary has a human-readable description and may include ad
 *** Experimenter <nowiki>{hedId=HED_0012472} [Person who is the owner of the experiment and has its responsibility.]</nowiki>
 ** Agent-trait <nowiki>{hedId=HED_0012473} [A genetically, environmentally, or socially determined characteristic of an agent.]</nowiki>
 *** Age <nowiki>{hedId=HED_0012474} [Length of time elapsed time since birth of the agent.]</nowiki>
-****  <nowiki># {takesValue, valueClass=numericClass, unitClass=timeUnits,hedId=HED_0012475}</nowiki>
+****  <nowiki># {takesValue, valueClass=numericClass, unitClass=timeUnits, hedId=HED_0012475}</nowiki>
 *** Agent-experience-level <nowiki>{hedId=HED_0012476} [Amount of skill or knowledge that the agent has as pertains to the task.]</nowiki>
 **** Expert-level <nowiki>{relatedTag=Intermediate-experience-level, relatedTag=Novice-level, hedId=HED_0012477} [Having comprehensive and authoritative knowledge of or skill in a particular area related to the task.]</nowiki>
 **** Intermediate-experience-level <nowiki>{relatedTag=Expert-level, relatedTag=Novice-level, hedId=HED_0012478} [Having a moderate amount of knowledge or skill related to the task.]</nowiki>
diff --git a/standard_schema/prerelease/HED8.4.0.xml b/standard_schema/prerelease/HED8.4.0.xml
index 6a6053f..dc3ee47 100644
--- a/standard_schema/prerelease/HED8.4.0.xml
+++ b/standard_schema/prerelease/HED8.4.0.xml
@@ -4193,6 +4193,10 @@ Each term in this vocabulary has a human-readable description and may include ad
                         <name>valueClass</name>
                         <value>numericClass</value>
                      </attribute>
+                     <attribute>
+                        <name>unitClass</name>
+                        <value>timeUnits</value>
+                     </attribute>
                      <attribute>
                         <name>hedId</name>
                         <value>HED_0012475</value>
diff --git a/standard_schema/prerelease/hedtsv/HED8.4.0/HED8.4.0_Tag.tsv b/standard_schema/prerelease/hedtsv/HED8.4.0/HED8.4.0_Tag.tsv
index da435e5..9bdff76 100644
--- a/standard_schema/prerelease/hedtsv/HED8.4.0/HED8.4.0_Tag.tsv
+++ b/standard_schema/prerelease/hedtsv/HED8.4.0/HED8.4.0_Tag.tsv
@@ -500,7 +500,7 @@ HED_0012471	Experiment-participant	3	Agent-task-role		Someone who takes part in
 HED_0012472	Experimenter	3	Agent-task-role		Person who is the owner of the experiment and has its responsibility.	
 HED_0012473	Agent-trait	2	Agent-property		A genetically, environmentally, or socially determined characteristic of an agent.	
 HED_0012474	Age	3	Agent-trait		Length of time elapsed time since birth of the agent.	
-HED_0012475	Age-#	4	Age	takesValue, valueClass=numericClass		Age and (valueClass some numericClass)
+HED_0012475	Age-#	4	Age	takesValue, valueClass=numericClass, unitClass=timeUnits		Age and (valueClass some numericClass) and (unitClass some timeUnits)
 HED_0012476	Agent-experience-level	3	Agent-trait		Amount of skill or knowledge that the agent has as pertains to the task.	
 HED_0012477	Expert-level	4	Agent-experience-level	relatedTag=Intermediate-experience-level, relatedTag=Novice-level	Having comprehensive and authoritative knowledge of or skill in a particular area related to the task.	Agent-experience-level and (relatedTag some Intermediate-experience-level) and (relatedTag some Novice-level)
 HED_0012478	Intermediate-experience-level	4	Agent-experience-level	relatedTag=Expert-level, relatedTag=Novice-level	Having a moderate amount of knowledge or skill related to the task.	Agent-experience-level and (relatedTag some Expert-level) and (relatedTag some Novice-level)