The Antec ISK300-65 has a the Mini-ITX form factor. Mini-ITX is even smaller than Micro-ATX, allowing PC builders the opportunity to create a low-performance, but discreet and low-power system. Using the Mini-ITX standard, the case can house motherboards and power supplies with form factors Array. The dimensions of the case itself (LxWxH) are 328mm x 222mm x 96mm.

The Antec ISK300-65 has one expansion slots, so there is very little room for extra components, which may be a deciding factor when planning on the longevity and build type of a PC system. The case has one 5.25" drive bays, which is enough room for an optical drive but little else, and with just one 3.5" drive bay, there is basically no room at all for expansion. There is also no 2.5" drive bay for a laptop-sized HDD or solid-state drive.