Semperfli Spyder thread is a traditional tying thread, was specially developed to be semi translucent so that the threads help adopt the shade of the fly pattern. Spyder has 2 fine strands of thread twisted together. It has a breaking strain of approximately 400gm - for comparison tests show Uni Caenis to have a breaking strain of 85g & Danville Spiderweb breaking strain is approximately 142gm. The strength of Spyder in comparison will give the fly tyer confidence when tying small flies that their thread will hold better. With 2 strands Spyder will also lay reasonably flat when tying flies.
Spyder is aimed for fly tyers wanting to tie small flies as an alternative to threads like Uni Caenis or Whisp which are weaker threads. In developing Spyder the team wanted a micro thread which had some strength, laid flat