The Stop Silent Light Backwater Flap

Easily Installed. Always Active.

The Stop Silent light check valve has been developed for the waste water house connection. Installed in seconds, Stop Silent Light ensures reliable backflow protection as well as longevity.

One Minute Installation!


Discover the many features of the Stop Silent Light backwater flap!

Avoid backflow of toilet water thanks to the Stop Silent Light anti-reverse device.

During heavy rainfall the sewer systems can fill up and cause back flow in foul drains. A large volume of water can flow back into basements and other low-lying bathrooms in a short period of time causing problems like overflowing toilets. [click here to learn more about it]

A pipe overlooking nature allows the intrusion of small animals. The "frog valve" function of Stop Silent Light prevents the infiltration of this type of animal and secures your pipes.

The open outlet of a pipeline into nature allows the ingress of insects, amphibians, birds and rodents into the drainage system. This can cause various problems upstream. [click here to learn more about it]

The installation of a Stop Silent Light® check valve makes it impossible for sewer gases to move and therefore prevents the spread of bad odors.

The stench of sewer gases is unpleasant. Air or gases in the pipeline start to move with a low temperature difference that is called the chimney effect. The installation of a Stop Silent Light valve prevents the movement of these gases out of the sewer system. [click here to learn more about it]

Make sure you have a Stop Silent Light backflow check valve to prevent flooding of the streets of your municipality.

Flood walls can prevent street flooding but sometimes the road gullies are still connected to water bodies that allow back flow through the street drainage system. Installation of Stop Silent Light check valves on these gully connections prevent this back flow and ensure that the roads are not flooded. [click here to learn more about it]


The Stop Silent Light® expander clamp can be operated from both sides and allows installation in the inlet or outlet of the access chamber/junction.

It can either be installed in existing drainpipes or manholes.


Due to a small build-up of water, a relatively low pressure is exerted on the diaphragm, which then opens upwards. If the flow stops, the sealing lip restores and closes the valve. In back pressure, the rubber membrane is filled and pressed against the pipe wall.


DN 100 – 300 (bigger on enquiry)

Featured Article (German)

"Geeignete Rückstausicherungen wählen

Rückstausicherungen können vor unliebsamen Überraschungen mit hohen Kosten aufgrund von Schäden an Inventar, Böden und Wänden durch das rückstauende Wasser schützen. Die Firma Lasso Technik AG bietet mit der Rückstausicherung Stop Silent Light eine adäquate Lösung für den zuverlässigen Rückstauschutz an.” – Fery Lipp für planer+installateur


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Phone UK: 0151 324 0021

Phone IE: 01 484 7832


Rest of the world

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Any person interested in exchanging good practices with us by promoting Stop Silent Light is invited to contact us.