1/4” and 5/16” screwdriver hex insert Tri-Wing ® Bits. The Tri-Wing bit, also known as triangular slotted, screw drive has three radial slots and is used extensively in the aerospace industry.Tri-Wing Bits, as the name suggests, is a screw with three ”wings” and a small triangular hole in the center. Each The Tri-Wing Bit is manufactured to the tightest tolerances in the industry, most are even tighter than licensing agreement requirements.Our Tri-Wing Bits meet the most stringent government and military specifications. The Tri-Wing screw drive is commonly used in aerospace applications.