The BugDorm-4M insect rearing cages are cubic or rectangle cages of various sizes. They all use fiberglass to support the structure, making the cages lightweight and easy to carry and store. The fiberglass framework is constructed outside the enclosure, minimizing gaps for insects to hide. The bottom of these cages is soft. You can install the acrylic floor (sold separately) to support the bottom when carrying heavy items is required.