This listing is for a replacement Oval push button and flush valve to suit an Impulse cistern with an oval hole for the flush button. The new button will not work with your existing flush valve, however.
Please note that the chrome push button will look different to the image shown, and you will need to fit all the parts in the pack for this product to work.
You will need to remove your cistern from the toilet pan to fit this new flush valve and push button.