30x30cm cubes.
 
Perfect for housing a single big mantis, two katydids, or up to a few small phasmids. It can fold flat to save space when not used.
 
Made from mostly mesh, with one wall being transparent plastic for viewing. It allows for great ventilation but also doesn't hold humidity well, so make sure to spray your inverts regularly with clean water. You can add a container of coco fiber at the bottom for added humidity.