In most of my smaller kits I keep an AMK Heatsheat, a large trashbag (80"x52") and 25' of reflective tent cord or 550 cord (in the larger of my small kits)

For my field PSK I carry only the AMK Heatsheat and 12' of reflective tent cord or 550 cord.

In my 24 hour kit, wildland kit, and my BOB where it is more likely that my Shelters will need to be taken down and the materials reused, I keep more durable materials. In my BOB and 24 hour kit I keep a Blaze orange 10'x12' Silicone Nylon tarp, 50' of 550 Cord, an AMK Emergency Bivy, (2) AMK Heatsheats and (2) 80"x52" trash bags. In my IA pack (wildland) I carry a Silicone Nylon Poncho and a AMK Emergency Bivy and 50' of 550 Cord.