diff --git a/media.go b/media.go
index 079e68a..5a4fa8a 100644
--- a/media.go
+++ b/media.go
@@ -5,12 +5,12 @@ import (
 )
 
 const (
-	// _BigPicture :nodoc:
-	_BigPicture = "big_picture"
-	// _LargeIcon :nodoc:
-	_LargeIcon = "large_icon"
-	// _IOSAttachment :nodoc:
-	_IOSAttachment = "ios_attahcment"
+	// BigPicture :nodoc:
+	BigPicture = "big_picture"
+	// LargeIcon :nodoc:
+	LargeIcon = "large_icon"
+	// IOSAttachment :nodoc:
+	IOSAttachment = "ios_attahcment"
 )
 
 // GeneratePushNotificationMediaURL Generates manipulated media URL for push notification purpose
@@ -26,13 +26,13 @@ func GeneratePushNotificationMediaURL(cdnURL, mediaSrcURL, imageType string) str
 	var param string
 	switch imageType {
 
-	case _LargeIcon:
+	case LargeIcon:
 		param = "image/upload/fl_progressive,fl_lossy,c_fill,g_face,q_auto:best,w_256,ar_1:1"
 
-	case _BigPicture:
+	case BigPicture:
 		param = "image/upload/fl_progressive,fl_lossy,c_fill,g_face,q_auto:best,w_1440,h_720"
 
-	case _IOSAttachment:
+	case IOSAttachment:
 		param = "image/upload/fl_progressive,fl_lossy,c_fill,g_face,q_auto:best,w_1024,h_1024"
 	}
 
diff --git a/media_test.go b/media_test.go
index c9edd51..a0a5841 100644
--- a/media_test.go
+++ b/media_test.go
@@ -8,6 +8,6 @@ import (
 
 func Test_GeneratePushNotificationMediaURL(t *testing.T) {
 	externalMediaURL := "https://this.is/test/image/upload/123/234.jpg"
-	res := GeneratePushNotificationMediaURL("https://this.is", externalMediaURL, _LargeIcon)
+	res := GeneratePushNotificationMediaURL("https://this.is", externalMediaURL, LargeIcon)
 	assert.Equal(t, "https://this.is/image/upload/fl_progressive,fl_lossy,c_fill,g_face,q_auto:best,w_256,ar_1:1/123/234.jpg", res)
 }