Made from Gel Spun Yarn (GSP), this stuff is a amazing. It is the strongest fly tying thread you will find but so thin it can be made to disappear. Use the 6/0 streamer patterns or anytime you really need to crank down- it is ultra strong and designed for those large flies! No need for different colors. Just take a marker to mark your thread before whip finish, then coat with a UV resin for a beautiful finished fly. Recommended you use with ceramic bobbin. 100m spool.