The Klein Tools 56250 Wire Marker Book is a must-have tool for professionals in the electrical industry. This marker book features wire markers from 1-48, making it easy to identify and organize wires in any project. The brand, Klein, is known for its quality and durability, ensuring that this tool will last a long time. This wire marker book is perfect for use in a variety of settings, including in the business and industrial sectors. It is also important to note that it comes with a California Prop 65 Warning. Overall, this is a great tool for anyone in need of a reliable and efficient way to mark and organize wires.