Porsche Hex Shank Insert Torx Drive Bit (5/16").

This is a Torx T-30 insert bit with a 5/16 inch hexagonal shank and an overall length of 1-1/4 inches. It is designed for use in power screwdrivers or drills with a 5/16 inch hex drive chuck to drive Torx T-30 screws. The larger 5/16 inch shank size indicates it's likely for heavier-duty applications compared to the standard 1/4 inch hex shank bits.