The M3 Boa Replacement Repair Kit fits the Korkers Chrome, Metal head and Darkness boots. This is a complete repair kit designed to fit 1 (left or right) boot in the event a Boa component needs to be replaced. It's an excellent field repair kit and is small enough to keep in a vest or jacket pocket. It includes the knob, reel, tool, lace combo that is designed for repairing or replacing your lacing system on your Korkers boots.