Ultra Tech™ 0 to 8" SAE and Metric Stainless Steel Digital Caliper (1478) by General Tools®. The #1478 8 In. Steel Digital Caliper can make inside, outside, depth and step measurements in inches or millimeters. If you’re looking for a reliable solution to get your job done with the ultimate accuracy, this top-notch measuring tool is right up to your alley. It is designed to help you maintain precision quality control on all the stages of your project. Made utilizing industry-leading materials and high-end equipment, this tool features an ergonomic design for uncompromising comfort and ease of use.