I was in the Volvo/Land Rover/Audi/Porsche dealer yesterday so they could finish some pre-delivery work on my Land Rover that was awaiting a part which had arrived.
I came across an amazing product by Volvo - Life Paint. It comes in small spray cans and is a completely invisible paint that can be applied to anything.
What is the point of invisible paint, you ask?
Ah - here is the clever part. At night, when car headlights etc shine on it, it lights up like 3M Scotchlite fabric!
You can spray it on anything - cycle helmets, back packs, clothes, bike frames, running jerseys, running shoes, dog collars etc etc.
Brilliant, eh?