This Klein Tools 85518 Multi-Bit Screwdriver/Nut Driver Set is the perfect addition to any tool collection. With a variety of additional bits, a bit holder, a nut driver, and a bi-material handle, this set has everything you need to tackle any screwdriver or nut driver task. The star size includes T 10 T15, and the system of measurement is standard (SAE). Made of plastic and steel, this set is durable and built to last. Whether you're a professional mechanic or a DIY enthusiast, this Klein Tools set is sure to provide the tools you need to complete any project. Add it to your collection today!