These are thinner cushions,  designed to allow proper fit for Discoblox for plates with a radius kingpin, for example, the Reactor, Revenge and Rival plates.
 
Different cushion hardnesses are available, so you can create the set-up you'd like!  
 
Other plates with a radius kingpin, do not require this kit, as the kingpins are longer, eg. Luna, Rookie and Sunlite plates.
 
Full fitting instructions are included.