diff --git a/REFERENCE.md b/REFERENCE.md
index 863c8ff..c5ae5da 100644
--- a/REFERENCE.md
+++ b/REFERENCE.md
@@ -24,6 +24,10 @@ Configures IcingaDB
 * `icingadb::redis::service`: Manage IcingaDB Redis server service
 * `icingadb::service`: Manage IcingaDB service
 
+### Data types
+
+* [`IcingaDB::RetentionOptions`](#IcingaDB--RetentionOptions)
+
 ## Classes
 
 ### <a name="icingadb"></a>`icingadb`
@@ -405,14 +409,7 @@ Default value: `undef`
 
 ##### <a name="-icingadb--retention_options"></a>`retention_options`
 
-Data type:
-
-```puppet
-Hash[Enum[
-      'acknowledgement','comment','downtime',
-      'flapping','notification','state'
-  ], Integer[1]]
-```
+Data type: `IcingaDB::RetentionOptions`
 
 Map of history category to number of days to retain its data in order to
 enable retention only for specific categories or to override the number
@@ -759,3 +756,18 @@ Data type: `Stdlib::Absolutepath`
 
 
 
+## Data types
+
+### <a name="IcingaDB--RetentionOptions"></a>`IcingaDB::RetentionOptions`
+
+The IcingaDB::RetentionOptions data type.
+
+Alias of
+
+```puppet
+Hash[Enum[
+    'acknowledgement','comment','downtime',
+    'flapping','notification','state'
+  ], Integer[1]]
+```
+
diff --git a/manifests/init.pp b/manifests/init.pp
index 9752057..d29faae 100644
--- a/manifests/init.pp
+++ b/manifests/init.pp
@@ -178,10 +178,7 @@
   Pattern[/^\d+\.?\d*[d|h|m|s]?$/]               $logging_interval       = '20s',
   Optional[Integer[1]]                           $retention_history_data = undef,
   Optional[Integer[1]]                           $retention_sla_data     = undef,
-  Hash[Enum[
-      'acknowledgement','comment','downtime',
-      'flapping','notification','state'
-  ], Integer[1]]                                 $retention_options      = {},
+  IcingaDB::RetentionOptions                     $retention_options      = {},
 ) {
   require icingadb::globals
 
diff --git a/types/retetionoptions.pp b/types/retetionoptions.pp
new file mode 100644
index 0000000..eade6c9
--- /dev/null
+++ b/types/retetionoptions.pp
@@ -0,0 +1,7 @@
+type IcingaDB::RetentionOptions = Hash[
+  Enum[
+    'acknowledgement','comment','downtime',
+    'flapping','notification','state'
+  ],
+  Integer[1]
+]