Tri-Wing Screwdriver Insert Bits from MRO Tools. 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.