Bumpons, also known as Bump Dots, are a fantastic, simple product for anyone who is visually impaired and wants to put a tactile mark on something. They are small rubber dots that come in a variety of different shapes, sizes and colours, and they can easily be stuck onto almost anything. In our house, we have some on the microwave as the buttons are touchscreen, and we also have some on our washing machine controls so I can feel which setting I’m putting the washing on. These are just two examples though, you can use them to put a small tactile mark on anything you want. They are not water resistant though, so try not to put them on anything that could get wet.
The link below is to a pack available from the RNIB which contains eight different varieties of bumpon shapes and colours, however if there is a particular type you prefer, you could shop around and try to find a pack of those particular ones. Just google “Bumpons for visually impaired” and that should give you plenty of results.