Also available in single-color, red, white, or amber. I have installed some at the top corners of my trailer (red/rear, amber/front) because for a trailer my size, top corner clearance lights are not required by law, but I thought some reflectors would be useful.
Except I didn't leave a place for reflectors! <sigh>
With some knife work, I split it into 1" wide strips. I paid $2 for a foot of red at my local trailer supply. They cut very generously and I got 15" for my two bucks! I cut it in to 10 @ 1"x3" pieces, and it went a LONG way! Nobody driving behind me will miss my little trailer!
The amber is harder to find - most places only have red and white. I found short chunks on eBay. Got 4@ 2"x9" strips for $3, including shipping.
The seller still has more:
http://www.ebay.com/itm/271217070214?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649The amber hasn't arrived yet, but I will use it to do the similar application to the front of my trailer.