diff --git a/example/GetETFCodeNumber/main.go b/example/GetETFCodeNumber/main.go
new file mode 100644
index 0000000..71a4873
--- /dev/null
+++ b/example/GetETFCodeNumber/main.go
@@ -0,0 +1,29 @@
+package main
+
+import (
+	"strings"
+
+	"github.com/injoyai/logs"
+	"github.com/injoyai/tdx"
+)
+
+func main() {
+	cs, err := tdx.NewCodes2()
+	logs.PanicErr(err)
+
+	ls := cs.GetETFCodes()
+
+	shNumber := 0
+	szNumber := 0
+	for _, v := range ls {
+		switch {
+		case strings.HasPrefix(v, "sh"):
+			shNumber++
+		case strings.HasPrefix(v, "sz"):
+			szNumber++
+		}
+	}
+
+	logs.Debug("sh:", shNumber)
+	logs.Debug("sz:", szNumber)
+}
diff --git a/protocol/unit.go b/protocol/unit.go
index 6d6c6ea..0384c1d 100644
--- a/protocol/unit.go
+++ b/protocol/unit.go
@@ -286,7 +286,7 @@ func IsETF(code string) bool {
 		return true
 
 	case code[0:2] == ExchangeSZ.String() &&
-		(code[2:4] == "15" || code[2:4] == "16"):
+		(code[2:4] == "15"):
 		return true
 	}
 	return false