The Abbey Bike Tools Decade Part Mid Plate is an alternate plate for the Decade Chain Tool Complete, with a choice of a the 1/8” or AXS model.
The first is for use with wide 1/8” track and single speed chains, while the second is crafted specially to hold the SRAM AXS Road Chain. Please note that it is not required when working with 12 speed chains from other manufacturers.
Both are intended to replace the stock mid plate of the Decade Chain Tool when you're working with the allotted chains and will hold them firmly in place while they're broken or repaired.