Apex 1/4”-24 screw shank for 1/4” hex insert bits. Bit holders from Apex offer the flexible use of insert bits with a variety of tools used throughout the aviation industry. With Apex Bit Holders, you get economy and flexibility. Apex quality begins with select raw materials, only high grade tool steel is used. Each tool is manufactured to the tightest tolerances in the industry. Closer tolerances also mean a better fit and less cam-out or stripping, which in turn keeps work areas free of damage and reduces incidence of bit failure and costly re-work.