diff --git a/soundtrigger/ISoundTrigger.cpp b/soundtrigger/ISoundTrigger.cpp
index 4df2068..25332a4 100644
--- a/soundtrigger/ISoundTrigger.cpp
+++ b/soundtrigger/ISoundTrigger.cpp
@@ -37,7 +37,7 @@
 class BpSoundTrigger: public BpInterface<ISoundTrigger>
 {
 public:
-    BpSoundTrigger(const sp<IBinder>& impl)
+    explicit BpSoundTrigger(const sp<IBinder>& impl)
         : BpInterface<ISoundTrigger>(impl)
     {
     }