Most of us use premade drag rigs or have the drag harness in turnout jackets. This is another one of those things to keep in your pockets for a just-in-case. We used 1/2" rescue rope, but smaller size will work. The nice thing about 1/2" it keeps it's shape a little better for the loops. Take 20 feet of rope and find the center, tie an inline eight. At the two ends tie an eight on each one. You may have to adjust the loops until you get the right length. This works great for drags. With a little practice wearing a blackout mask you can deploy and have this on a downed firefigther in less than 20 seconds. The end loops go over the legs,  run the center loop up the back and go up to the top of the scba and run it under the pack. By running it throught he top of the scba it keeps everything in line while dragging. The center loop gives you an attachment point so you can crawl and drag a downed firefighter behind.

It's for drags only, but It's always good to have more than one way to move a downed firefigther out.