diff --git a/mms-lib/include/mms_connman.h b/mms-lib/include/mms_connman.h
index d5c85be..ac90cf7 100644
--- a/mms-lib/include/mms_connman.h
+++ b/mms-lib/include/mms_connman.h
@@ -17,6 +17,12 @@
 
 #include "mms_lib_types.h"
 
+/* Instance */
+struct mms_connman {
+    GObject object;
+};
+
+/* Class */
 typedef struct mms_connman_class {
     GObjectClass parent;
     char* (*fn_default_imsi)(MMSConnMan* cm);
diff --git a/mms-lib/include/mms_handler.h b/mms-lib/include/mms_handler.h
index b313870..e65f5ba 100644
--- a/mms-lib/include/mms_handler.h
+++ b/mms-lib/include/mms_handler.h
@@ -56,6 +56,11 @@ typedef enum _mmm_delivery_status {
 /* Read status */
 typedef MMSReadStatus MMS_READ_STATUS;
 
+/* Instance */
+struct mms_handler {
+    GObject object;
+};
+
 /* Class */
 typedef struct mms_handler_class {
     GObjectClass parent;
diff --git a/mms-lib/include/mms_lib_types.h b/mms-lib/include/mms_lib_types.h
index 6e916a1..d230827 100644
--- a/mms-lib/include/mms_lib_types.h
+++ b/mms-lib/include/mms_lib_types.h
@@ -64,8 +64,8 @@ typedef struct mms_attachment_info {
 } MMSAttachmentInfo;
 
 /* Types */
-typedef GObject MMSHandler;
-typedef GObject MMSConnMan;
+typedef struct mms_handler MMSHandler;
+typedef struct mms_connman MMSConnMan;
 typedef struct mms_log_module MMSLogModule;
 typedef struct mms_dispatcher MMSDispatcher;
 typedef struct mms_connection MMSConnection;
diff --git a/mms-ofono/src/mms_ofono_connman.c b/mms-ofono/src/mms_ofono_connman.c
index 5ba32dc..f84dc71 100644
--- a/mms-ofono/src/mms_ofono_connman.c
+++ b/mms-ofono/src/mms_ofono_connman.c
@@ -26,7 +26,7 @@ MMS_LOG_MODULE_DEFINE("mms-ofono-connman");
 
 typedef MMSConnManClass MMSOfonoConnManClass;
 typedef struct mms_ofono_connman {
-    GObject cm;
+    MMSConnMan cm;
     guint ofono_watch_id;
     GDBusConnection* bus;
     MMSOfonoManager* man;