The non-return flaps of Lasso Technik AG are equipped with a membrane that reliably prevents the backflow of liquids and gases. When the membrane is closed, only a low noise level is generated, so water hammer is excluded. This backflow prevention device guarantees reliability at all times since it works even when the water contains granules or sand. In addition, our backflow preventers act as raw filters and secure pumps and systems of this type. The check valve is extremely durable because no moving mechanical parts can wear out because it does not contain any.