Spirit River UV Estaz Chenille is a twisted core wrapped mylar. It makes all sorts of patterns look better, especially woolly buggers and egg patterns.

Spirit River UV Estaz Chenille was popularized by Steve Probasco. Wind it like wet fly hackle (folding the fibers back with each wrap) for the best results. Use for woolly buggers, nymphs, salmon/steelhead, and saltwater patterns.
Grande is a longer, fuller version. All the colors are dyed over pearl. Ideal for producing large profile saltwater and bass flies.

What is UV2 Technology?

It is a double dye process to give all of their UV2 materials and flies added UVF/UVR ultraviolet wavelengths. UV Florescence is used on everything from street signs to fly tying materials. UV Reflectance on the other hand is a spectrum of wavelengths humans cannot visually see; yet it is extremely common in the animal and insect world. UVR allows mayflies to find mates, and bees to find flowers. Fish can see it, and they love it. UV materials and flies are becoming much more popular within the fly-fishing world because of the success they bring while on the water.