Open-air Mini-itx Enclosure With five drive bays, one expansion slot, and a top 150mm TriCool blue LED fan, the Mini Skeleton-90 can do it all: The Mini Skeleton-90 features the same revolutionary open-air design as the Skeleton, only in a compact Mini-ITX frame. The Mini Skeleton-90 features the same revolutionary open-air design as the Skeleton, only in a compact Mini-ITX frame. With five drive bays, one expansion slot, and a top 150mm TriCool blue LED fan, the Mini Skeleton-90 can do it all: