- High-Quality Material: Crafted from premium bearing steel, our step drill bits feature a titanium-plated surface that is tarnish-resistant, rust-proof, and exceptionally durable, ensuring long-lasting performance. - Innovative Design: The three-sided shank and dual-propel cutting head enable rapid, uniform drilling while minimizing the risk of chips or splitting, particularly when working with tough materials. - Time Efficiency: With 29 different opening sizes ranging from 4mm to 32mm, you can drill or enlarge a variety of holes using a single bit, eliminating the need for frequent bit changes and enhancing productivity. - Comprehensive Set: This set includes 1 x 4-12mm step drill bit, 1 x 4-20mm step drill bit, 1 x 4-32mm step drill bit, and 3 x HSS twist drill bits. It comes with a portable plastic case for easy storage and organization. Use Scenarios: 1. Perfect for electricians needing to create precise holes for wiring installations without changing bits repeatedly. 2. Ideal for plumbers who require a versatile solution to enlarge pipe holes in various materials quickly and efficiently. 3. Great for DIY enthusiasts looking to tackle home improvement projects, providing the flexibility to drill multiple sizes with one tool. Choose our step drill bits for a reliable and efficient drilling experience, designed to meet your diverse needs with ease and precision.