The Macintosh IIsi was a compact 3-box desktop unit, effectively a cut-down Macintosh IIci in a smaller case, made cheaper by the redesign of the motherboard and the deletion of all but one of the expansion card slots (a single Processor Direct Slot). It was introduced as a low-cost alternative to the professional desktop models for home use, but offered more features and performance than the LC series. It had colour and could drive a number of different external monitors, with a maximum screen resolution of 640 x 480 in 8-bit colour.