Socket head (Hex-Allen) screwdriver bits from Apex Fastener Tools formally Cooper Tools. The socket head (Hex-Allen) bit is one of the most common screw drives in not only the aviation industry, but the automotive repair, technology and heavy industry sectors. This screw drive is also common in heavy industry environments. The Apex brand has always stood for quality design and is constructed to last longer than cheaper alternatives.Apex quality begins with select raw materials, only carefully chosen, high grade tool steel is used. Each Apex bit is manufactured to the tightest tolerances in the industry, most are even tighter than licensing agreement requirements and all Apex bits meet the most stringent government and military specifications.