4mm; Length: 5.6 in. BriteGuard Plated Stubby Balldriver L-wrench. Balldriver Screwdrivers feature ergonomically designed ComfortGrip handles. This handle includes a hard thermoplastic core for strength and split resistance, and a soft rubber outer coating to ensure maximum comfort and grip. Only available from Bondhus, Protanium steel blades mean these are the strongest ballpoints available. These screwdrivers provide the greatest time savings for maintenance, assembly, and adjustment of hexagonal socket screws. The handles are proportioned to provide maximum torque without breakage.