Veevus G.S.P Thread- The Strongest Thread on the Planet . Spin hair, pull as hard as you want. Veevus has given it's G.S.P or Gel Spun Polyethylene a slight twist so that it lays flat in the tying process. This flat strong tying thread is absolutely the best thread you can use for tying spun hair flies. We also really like it for making egg patterns. Each spool of thread contains 75 meters which is 67% more than any other manufacturer we are aware of. GSP thread is a must add to your fly tying kit. Big flies, spun hair flies, egg patterns, and more. Available in 30 Denier white, 100, 150, 200 Denier Black and white. 30 Denier being the lightest for smaller hook sizes and going up to 200 if you are tying massive Bass or Saltwater patterns.