Definitely big enough openings and tunnels space for large breed cats. Your lovely cats can play in it, sleep in it, sleep on top of it, hide in it, play around it… you name it. This is a fantastic toy/bed/tunnel. You can keep it mostly assembled, except you only tied together two tube ends to let the cats freely run through the untied two ends. There is a padded cushion in the exterior center of the doughnut so she can climb on top and "falls" into it without getting hurt. This is their favorite toy/bed/tube, and on top of it all, You can put their turbo scratcher in the center to add another level of play. Very light weight, can pick up and put it anywhere. Recommend this product especially with multiple cats.