185-000X-BH-4.25 Apex 1/4” Hex Insert Ball End Hex Bit. Apex Ball End Hex Bits w/ a 1/4” Hex Insert are manufactured using a proprietary steel and heat treat process that yields greater strength and a longer bit life. Apex Ball End Hex Bits are manufactured using a cutting-edge machining process that results in tighter tolerances, superior product consistency and a better and more consistent fit to fasteners leading to better torque transfer. Apex Ball End Hex Bits are designed with one of the most common screw drives in the aviation industry, automotive repair, technology and heavy industry sectors.