Screwdriver Bit Professional Double Ended Screw Driving Set Tools Kit 41 PC PREMIUM S2 MATERIAL - Manganous phosphate treatment surface with maximizing rust and corrosion protection, Calibrated heat-treated process comes with higher quality, the hardness can reach 56HRC and bits withstand more torque and reduce wear-outs for durability and reliability 41 Bits with ANSI Standard - Precise match, screw driving set includes 41 pieces, featuring insert Phillips, slotted, Includes double-ended bits. Ideal for almost all driving and fastening applications. Use for almost all driving and fastening applications - Bits are extra hard and designed to withstand the high torque associated with today's more powerful impact drivers. Forged tips create a stronger and more flexible torsion zone reducing breakage and extending bit life. Made of the highest quality S2 tool steel for durability. The proven sub-zero tempering process gives a bit longer life. Package Case - Top quality, hard plastic carrying kit is portable and conveniently packs all tools for simple storage and organization To make carrying these bits to the job easy, this kit comes in a durable blow-molded the plastic case that keeps them protected and organized. Made of the highest quality S2 tool a steel construction will ensure these bits are up to whatever you can throw their way. S2 high-quality steel, this batch of the head using S2 high-quality steel, batch head surface for steel material color, from inside to outside are the same. Good material does not need to make the surface decoration through the exterior decoration, the quality of the batch is to look at the intrinsic material. Exquisite workmanship, each edge can be accurately locked screws, no damage to the screw, and the screwdriver head. Widely used for a manual electric screwdriver, screwdriver, drill, air, and other tools. Package List: 2-inch power bit (10) 2-inch double-ended bit (10) 2.5-inch double-ended bit (10) 4-inch double-ended bit (10) 4-inch bit holder (1)