The Starrett Universal Snug comes with spindle hole diameters 1/4 inch, 5/16 inch, 3/8 inch (6.3, 8, 9.5mm). Gripping hole diameters range from 3/32-1/4 inch used on holders with smaller clamp hole. Starrett tools are designed to be user-friendly. Whether you are an experienced professional or an amateur when it comes to home improvement, our tools are handy and accessible. Starrett has set the standard for precision, quality, and innovation. Our products are long-lasting and robust with excellent service and performance. Manufacturing long-lasting and easy to use tools that provide consistent and reliable performance since 1880, Starrett tools are made with the highest standard of quality and workmanship, manufacturing more than 5,000 various tools, gages, and instruments, providing fine precision tools for industrial, professional, and consumer markets worldwide.