diff --git a/ontology/saref4wear.ttl b/ontology/saref4wear.ttl
index b13ae23f95001a4d848bba4d0cf74a2fdcdb4fda..1851c15b704debda6681d700f3601b227d6c5576 100644
--- a/ontology/saref4wear.ttl
+++ b/ontology/saref4wear.ttl
@@ -8,6 +8,7 @@
 @prefix skos: <http://www.w3.org/2004/02/skos/core#> .
 @prefix vann: <http://purl.org/vocab/vann/> .
 @prefix voaf: <http://purl.org/vocommons/voaf#> .
+@prefix saref: <https://w3id.org/saref#> .
 @prefix s4wear: <https://saref.etsi.org/s4wear#> .
 @prefix dcterms: <http://purl.org/dc/terms/> .
 @base <https://saref.etsi.org/saref4wear#> .
@@ -239,10 +240,6 @@ s4wear:Control rdf:type owl:Class ;
                rdfs:subClassOf s4wear:Capability .
 
 
-###  https://saref.etsi.org/s4wear#Device
-s4wear:Device rdf:type owl:Class .
-
-
 ###  https://saref.etsi.org/s4wear#ElecticalSafety
 s4wear:ElecticalSafety rdf:type owl:Class ;
                        rdfs:subClassOf s4wear:Information .
@@ -383,7 +380,7 @@ s4wear:User rdf:type owl:Class ;
 
 ###  https://saref.etsi.org/s4wear#Wearable
 s4wear:Wearable rdf:type owl:Class ;
-                rdfs:subClassOf s4wear:Device ;
+                rdfs:subClassOf saref:Device ;
                 rdfs:comment """A wearable device is a device that is intended to be located near, on or in an organism.
 The definition of this concept satisfies the requirement WEAR-1."""@en ;
                 rdfs:label "Wearable device"@en .
@@ -404,6 +401,24 @@ The definition of this concept satisfies the requirement WEAR-2."""@en ;
               rdfs:label "Wearer"@en .
 
 
+###  https://saref.etsi.org/saref#Device
+saref:Device rdf:type owl:Class ;
+             rdfs:subClassOf [ rdf:type owl:Restriction ;
+                               owl:onProperty saref:controlsProperty ;
+                               owl:allValuesFrom saref:Property
+                             ] ,
+                             [ rdf:type owl:Restriction ;
+                               owl:onProperty saref:makesMeasurement ;
+                               owl:allValuesFrom saref:Measurement
+                             ] ,
+                             [ rdf:type owl:Restriction ;
+                               owl:onProperty saref:measuresProperty ;
+                               owl:allValuesFrom saref:Property
+                             ] ;
+             rdfs:isDefinedBy <https://saref.etsi.org/saref#> ;
+             rdfs:label "Device"@en .
+
+
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 #    Individuals
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