diff --git a/adapters/outboundgroup/urltest.go b/adapters/outboundgroup/urltest.go
index 7073b5e..c20340e 100644
--- a/adapters/outboundgroup/urltest.go
+++ b/adapters/outboundgroup/urltest.go
@@ -78,7 +78,7 @@ func (u *URLTest) fast() C.Proxy {
 		}
 
 		// tolerance
-		if u.fastNode == nil || u.fastNode.LastDelay() > fast.LastDelay() + u.tolerance {
+		if u.fastNode == nil || u.fastNode.LastDelay() > fast.LastDelay()+u.tolerance {
 			u.fastNode = fast
 		}