There are two superultra-duper reflective materials on earth. Two that stand out above all others. One is 3M's Scotchlite, which we sell in 2.25-foot x 1-inch rolls for $7, and the other is Reflexite, which we sell in 10-foot x 1-inch rolls for $10. Considering what they do (make you visible), they're both a bargain.

You can use one or the other or both, and here's the diffs:

Scotchlite is grey but shines up bright white. It is softer and wraps more easily around (to make the point), a thin stay on a rack. It blends in during the day and looks grey, so if you want low-key daytime with shrieking banshee at night, it's a good way to go.

The Reflexite we sell is schoolbus yellow. In daytime it shows up better, and daytime visibility is a concern, too. At night, it screams as loudly as Scotchlite does, but in schoolbus yellow. It doesn't wrap as well around pencil-sized rack members, but on anything bigger than a fat rack, no problem. Reflexite is made in two grades. This is the best one, with a 10-year guarantee. The same grade as the Dept of Transportation uses on commercial vehicles. This one was made for schoolbuses, hence the color.

They both work well on the inner  perimeter of rims between the spokes, and on helmets, fenders, seat stays, and crank arms. If you ride in traffic and at night, keep some of each around, ready to stick patches onto a lowly lit friend's bike after yours is all full up.

How to: Cut to shape, then use a knife to separate the tape from the backing. Dull or short fingernails will drive you nuts. The tape itself is super tough and sticky, quite easy to handle once the sticky part is exposed. You can lay it down wrong and restart many times. It is best to round edges, because if anytime in nine years it wants to lift off it'll be at a corner; but don't obsess about that (as I do). The stickum is good, and it'll stay.