REI carries a tent guy line cord that is yellow with reflective thread woven into the outer sheath. It is pricy, $15 for 50 feet. http://www.rei.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=3791&prmenbr=8000<br><br>It is strong, thin, brightly colored, and reflective. I use it for lanyards on my equipment. If you drop something, just shine your flashlight around and it will show up. I also put a band of reflective tape around all my equipment. <br><br>You can find plain old white tape at Home Depot and Lowes. Gall's, http://www.gallsinc.com/shop/viewproduct.jsp?catcode=140 , carries reflective tape in 8 colors in 4 widths in two lengths. I use orange for all my equipment. It serves to identify my equipment so if borrowed, it makes it easier to encourage people to return it to me. It also makes it easier to find if dropped. <br><br>Royal blue does not occur in nature except as water in the tropics. Blue Tarp blue is a good color to use when marking equipment you don't want to lose in a wilderness environment.