Stonfo Thread Splitter Stonfo Thread Splitter is a high precision fly tying tool that allows for quick and easy way to split multi-strand threads to make dubbing loops for smaller flies, smaller streamers, nymphs or dry fly bodies. This handy tool has been designed so a small, sharp splitting needle is positioned right at the center of the splitter where the thread is inserted. To use - simply insert the thread in the center groove of the splitter, tighten the thread over it by lifting the tool up and depress the spring-loaded needle upwards. The needle will split the thread and you can simply insert your fingers or a bodkin in the newly created loop. Check out Tim Cammisa's instructional video on how to use the Stonfo Thread Splitter to split the thread when fly tying: One of the video reviews of Stonfo Thread Splitter: