Most of the Sunday team have been riding guard sprockets for years, so the Knox was only a matter of time. It is machined out of 7075 aluminium with a full guard on one side, there to take the hit when you slip off a rail or blow a crankslide.

The important part is the clearance: the Knox is designed to fit larger chains, including half link chains, so it works with a wider range of setups than most guard sprockets. It measures 6mm thick.