Bi-format capability of Mini-ITX or Micro-ATX form-factor board allows to migrate from Micro-ATX to Mini-ITX and back over life time of system; possibility to have face on front or back side; effectively doubling capacity with good connection options. Two PCI slots riser card or CDD with either front or back access. Thanks to compact design chassis can be used in non-deep racks or in add-on mini-cabinets within limited spaces (bandwidth monitor, firewall, router, small server). Four chassis can be placed in the same 3U bay of standard 800mm deep rack with the help of holes in mounting brackets that allow to mount chassis with ½ U shift up or down.