It has a 28 hole configuration. Hub is Shimano SRAM 8/9/10 speed compatible. Also included is the head unit with charger, hub removal tool to access battery, Instruction manuals and training CD. Please note batteries will need to be replaced. The item "CycleOps Powertap ANT+ PowerMeter Hub 28H 130mm Shimano SRAM 8/9/10 with Computer" is in sale since Friday, September 24, 2021.This item is in the category "Sporting Goods\Cycling\Bicycle Components & Parts\Hubs". The seller is "quickjab27" and is located in Arvada, Colorado. This item can be shipped worldwide.