This thread is stranded GSP and has incredible strength for its size. Advertised as 'almost unbreakable', it allows tying techniques never before possible with minimal thread build-up. It is loosely twisted and, unlike other GSP threads, can be split for dubbing loops if desired, although it is fine enough to be doubled for loops as well. The white thread takes marker colors easily. 100 denier, 50 meters per spool.
Because GSP fibers are quite tough, they can damage the blade edge on fine scissors and stainless bobbins. Semperfli recommends using a ceramic bobbin and cutting with a razor blade. Nano Silk will take most dubbing waxes and this helps the thread stay in place as well as serve as a great dubbing thread. Although it is tough enough to make durable flies without a coating of head cement, UV cure and water-based cements can be used for appearance or texture. Solvent-based glues and coatings are not recommended as they might compromise the fibers' strength.