Reflective
From GummyCarbs
Tape
Orafol Reflexite
Reflexite seems to be the brightest reflective tape on the market. There are several versions.
V98 - more conformable for complex curves, stretches, can be repositioned, adhesive increases in strength over time
V92 - thicker, stiffer, less conformable, will not stretch, very strong adhesive
http://www.findtape.com/ was the cheapest source I found.