Body Stretch is the most frequently used material for Czech Nymph backs but can be used for thorax cases or translucent fly bodies of other fly patterns. Typical characteristic of this material is the possiblity to stretch it during fly tying. This is a really basic material for Czech Nymph tying!!! 2 strips about 15,8 in (401,3 mm) long and about 0,1 in (2,5 mm) wide.