The Apple IIGS featured a 2.8 MHz 65C816 processor with 16-bit and 24-bit addressing registers, an Ensoniq sound processor, more memory, better colors, more peripherals (with a swappable controller between IIe and IIc board models), some of which are compatible with those of the Macintosh (keyboard, mouse, LocalTalk network adapter) and GS/OS, an operating system derived from Mac OS. The Applied Engineering company developed several expansion cards for the Apple II range, including the PC Transporter, allowing a PC XT (NEC V30 processor, 768 kB RAM, CGA graphics mode) to be added under the hood. Note that Apple marketed a kit allowing to transform an Apple IIe into an Apple IIGS.