Upavon XO Shrimp Back is a synthetic shell back material designed specifically for the carapace on shrimp, scud, and crustacean patterns. It stretches over the body without bunching, ties down cleanly at the head and tail, and produces the translucent, segmented shell profile that makes a shrimp pattern read correctly to trout and saltwater fish at close inspection distance. It takes a permanent marker well if you want to add segmentation lines, and the material doesn't split or crack under repeated bending the way some shell back synthetics do.