They're quite a new device that only opens the valve once the flush is complete. A normal valve start to fill once the float starts to drop therefore a little more water is added to flush before it is finished, wasting water.
It's a development that follows some of the new water saving initiatives
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local