MF-25 Apex Universal Adapter, 1/4” Square Drive, Pin Lock. Apex 1/4” square drive universal adapters, male square to female square with pin lock. Apex 1/4” square drive universal adapters are manufactured using a proprietary steel and heat treat process that yields greater strength and a longer bit life. The cutting-edge machining process used to manufacture Apex 1/4” square drive universal adapters results in tighter tolerances, superior product consistency and a better and more consistent fit to fasteners leading to better torque transfer.