Should you lose or need to replace the chainring bolts on your 1st and 2nd gen 11-speed Dura-Ace and Ultegra series, this set of 4 genuine Shimano M8 x 10.1mm Gear Fixing Bolts is the proper replacement option. These are the same bolts as came stock with your crankset. The Torx T30 head interface is ideal for clean, proper installation (12-16 Nm) without stripping. Shimano preps with a light application of green threadlocking compound, or if you are the service-oriented type who checks your bolts and needs to change your rings more often for optimal event gearing, you can also use a small amount of standard grease. Keep in mind these bolts are threading directly into some costly road chainrings, so please use a torque wrench to keep both you and your rings safe from any damage.