diff --git a/include/binder/Binder.h b/include/binder/Binder.h
index f849fd4..3404881 100644
--- a/include/binder/Binder.h
+++ b/include/binder/Binder.h
@@ -80,7 +80,7 @@
 class BpRefBase : public virtual RefBase
 {
 protected:
-                            BpRefBase(const sp<IBinder>& o);
+    explicit                BpRefBase(const sp<IBinder>& o);
     virtual                 ~BpRefBase();
     virtual void            onFirstRef();
     virtual void            onLastStrongRef(const void* id);
diff --git a/include/binder/IInterface.h b/include/binder/IInterface.h
index 48c8b3b..be72d44 100644
--- a/include/binder/IInterface.h
+++ b/include/binder/IInterface.h
@@ -63,7 +63,7 @@
 class BpInterface : public INTERFACE, public BpRefBase
 {
 public:
-                                BpInterface(const sp<IBinder>& remote);
+    explicit                    BpInterface(const sp<IBinder>& remote);
 
 protected:
     virtual IBinder*            onAsBinder();