Shimano fct521 10 speed triple chainringsthese chainrings are extremely durable and when paired with the correct crankset they are perfect for long touring journeys the shimano range of steel chainrings is known as among the strongest in the world of cycling and these chainrings are no exception features bolt circle diameter 64mm material steel chain compatibility hyperdrive shimano hg x use trekking speed 10 speeda 2 year warranty is offered with all shimano products from chain reaction