The Nylon Shaft Test Kit Extended 6 Set from BULLS are black colored shafts consisting of nylon and are packed in a discount package with 6 different types, to feel the difference which shaft size you need for your darts. with every dart. They are available in a variety of sizes to suit your dart in length and feel. Sizes: XX-Short / Micro, X-Short, Short, In Between, Medium & Long. In addition, they also consist of different materials: nylon, carbon, plastic, metal, etc. In short, you can adjust your dart to your own taste and feeling by using different types of shafts.