When a chain has to do both front and rear shifting, certain compromises have to be made to make it work. With SRAM's XX1 chain, it's 1x11 all the time, so the chain can be narrower, stronger, faster, since it doesn't have to deal with a front derailleur. Since it only has to do rear shifts, gear changes are telepathically fast and feathery light. Its "wide tooth, narrow tooth" pattern perfectly matches the chainrings to hold onto your chain so dropped chains are a distant memory. SRAM's Hard Chrome tech gives the chain maximum strength, and a proprietary link finish provides improved life span too. Welcome to the future of mountain drivetrains.