All blades are made from high-quality steel, hardened and tempered for optimum performance. Use with Series 99® Handles which have a patented spring device that holds the shaft firmly yet permits quick, easy insertion and removal. Weller Xcelite has a full line of high-quality, durable precision hand tools, specialized tools, and expertly crafted kits for their specific task. For hobbyists and prosumers who depend on precision hand tools, Xcelite has been the favorite of service technicians for almost 100 years. 14 PC Tool Kit with Nutdrivers and Screwdrivers in a Roll Pouch. Series 99 service kits and sets are part of the Series 99 interchangeable blades, shanks and handles, which allows for easy replacement or expansion based upon your tool needs to speed up assembly and service repair work