In response, Apple introduced a range of relatively inexpensive Macs in October 1990. The Macintosh Classic, essentially a less expensive version of the Macintosh SE, was the least expensive Mac offered until early 2001. The 68020-powered Macintosh LC, in its distinctive "pizza box" case, offered color graphics and was accompanied by a new, low-cost 512×384 pixel monitor. The Macintosh IIsi was essentially a 20 MHz IIci with only one expansion slot. All three machines sold well, although Apple's profit margin on them was considerably lower than that on earlier models.