HOTBIN Mega Expansion KitAs the HOTBIN Mega is a modular system you can quite simply use the Expansion Kit to increase the capacity of your 450 litre model up to 700 litres. The innovative design and super insulating walls of the material keeps the HOTBIN HOT, creating a natural environment which quickly digests the contents, making HOT composting easier and faster all without having to add any composting accelerators or activators!