Sound Cycle by alexander muspratt-williams from uk

Very often, other city/road users don’t see or hear cyclists coming.
‘Sound-Cycle’ gives your bicycle a gentle voice so others can hear you approach, making cycling around the busy city safer.
‘Sound-Cycle’ is a modern, commercial re-work of a classic way to enhance one’s bicycle. It’s a cheap and simple addition to any bicycle, giving it a gentle voice so it can be heard. A gentle ‘Purrrrrrrrr’ is generated as the wheel turns and the spokes hit the coloured plastic card.