Quadra was the name used by Apple Inc. for most of its Macintosh computers built around the Motorola 68040 CPU. The first of these were the Macintosh Quadra 700 and 900, both introduced in 1991 with a CPU speed of 25 MHz. The former was a compact model using the same case as the Macintosh IIci, with a PDS expansion slot, while the latter was a new tower case with five NuBus expansion slots plus one PDS slot.