diff --git a/Sources/Classes/RSConfigBuilder.m b/Sources/Classes/RSConfigBuilder.m
index f7460e32..add4e719 100644
--- a/Sources/Classes/RSConfigBuilder.m
+++ b/Sources/Classes/RSConfigBuilder.m
@@ -60,6 +60,9 @@ - (instancetype) withFlushQueueSize: (int) flushQueueSize {
     if (config == nil) {
         config = [[RSConfig alloc] init];
     }
+    if (flushQueueSize < 1 || flushQueueSize > 100) {
+        return self;
+    }
     config.flushQueueSize = flushQueueSize;
     return self;
 }