Nymph body - Catgut CG05 - OliveBrown
Catgut is a great fly tying material and flies tied with catgut look very realistic.
Size L is for hooks #8 and #10
Size M is for hooks #12 and #14
Size S is for hooks #14 and #16
Size XS is for hooks #16 and #20
Similar to the material found in the best (and most expensive) tennis strings that have been used since the early 1800s, catgut used in fly fishing is a natural fiber extracted from the wall of intestines from cattle. Wet ribbon fibers are twisted together giving them a mono-filament finish.
The natural color is a dirty cream with the odd glassy clear patch. In its dry state, catgut is a stiff and quite springy cord. When soaked in water its physical/structural state changes dramatically. It swells noticeably and goes ultra-limp and the entire cord takes on a milky translucence.
Before fly-tying you should keep catgut in warm water for 3-5 min. When the material becomes translucent and soft you can use it. Don't place the entire material in water. Keep wet only the part that you are planning on using.
When the fly is complete DO NOT apply any coat (i.e. head cement) on the body!! You will negatively impact the properties of the catgut!!