The xt m8000 single chainring is a new 4 arm narrow wide chainring from shimano with hollow gear construction it has been extremely well thought through and features the same hooked teeth as the xtr deeper teeth with dce dynamic chain engagement to increase chain retention by 150 percent and prevents the chain from jumping out this all helps hold the chain firmly on uneven tracks while keeping chain noise and drag to a minimum and increases durability the hollow gear construction optimises