The E251 kit enables you to mount a Monokey top box to a bike’s original rack. It can be used with the stop light kit / remote control kit. Max load 10kg. The Z113C2 is a universal Monolock kit matching what is supplied with Monolock urban cases. Max load 3kg.
A note on load capacity:
The load carrying capacity of the plate is limited by its ability to absorb vibration. This is the reason why nylon Monokey plates typically have a higher load capacity than the aluminium plates. The load capacity specification relates to the contents of the top box and is extra to the weight of the box itself.