diff --git a/core/th7/th7.go b/core/th7/th7.go
index 40a2a2e..f6df0c3 100644
--- a/core/th7/th7.go
+++ b/core/th7/th7.go
@@ -82,5 +82,8 @@ func (t *TH7Adapter) GetPivdd() float64 {
 
 // Ratio table
 func (t *TH7Adapter) GetRatio() core.Ratio {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
 	return t.table
 }