What extensions can I use for the Zippi Rabbit Run, double height with underfloor mesh?

There are a variety of different extension packs available. 

You can extend the length: https://www.omlet.co.uk/shop/rabbit_products/zippi-run-and-playpen-spares/25668/extension_for_zippi_rabbit_run_with_roof_and_underfloor_mesh_-_double_height/ 

You can extend the width: https://www.omlet.co.uk/shop/rabbit_products/zippi-run-and-playpen-spares/27376/extension_for_zippi_rabbit_run_with_roof_and_underfloor_mesh_-_double_height_3_x_2_to_3_x_3/ 

Or you can extend both at the same time: https://www.omlet.co.uk/shop/rabbit_products/rabbit-runs-playpens-zippi-extensions/27385/extension_for_zippi_rabbit_run_with_roof_and_underfloor_mesh_-_double_height_3_x_2_to_4_x_3/.