they are the first to be available only with an Apple silicon system on a chip. These models re-introduced MagSafe, function keys, and some other elements that had been removed from the Touch Bar MacBook Pro. Alongside the redesigned M2 MacBook Air, Apple refreshed the 14- and 16-inch MacBook Pros with the Apple M2 chip. The model features the same chassis, albeit with changes to the system audio: speakers compatible with Spatial Audio and a headphone jack with support for high-impedance headphones. Intel-based Aluminum (2007–2008) The original MacBook Pro used the design of the PowerBook G4, but replaced the PowerPC G4 chips with Intel Core processors, added a built-in iSight camera, and introduced the MagSafe power connector. The optical drive was shrunk to fit into the slimmer MacBook Pro; it runs slower than the optical drive in the PowerBook G4 and cannot write to dual-layer DVDs. The 15-inch model was introduced in January 2006; the 17-inch model in April. In 2007, the 15-inch model added Intel Core 2 Duo processors, and LED-backlit displays, and 17-inch did in 2008. The 2007 revision received new Nvidia Geforce 8600M GT video cards and the 2008 revision upgraded the processors to "Penryn" cores while adding multi-touch capabilities to the trackpad. Both the original 15- and 17-inch model MacBook Pro computers come with ExpressCard/34 slots, which replace the PC Card slots found in the PowerBook G4. Initial first-generation 15-inch models retain the two USB 2.0 ports and a FireWire 400 port but drop the FireWire 800, until it was readded in a later revision. The 17-inch models have an additional USB 2.0 port, as well as the FireWire 800 port missing from the initial 15-inch models. All models now included 802.11a/b/g. Later models include support for the draft 2.0 specification of 802.11n and Bluetooth 2.1. The original case design was discontinued on October 14, 2008, for the 15-inch, and January 6, 2009, for the 17-inch. Models of the MacBook Pro built from 2007 to early 2008 (15") / late 2008 (17") using the Nvidia 8600M GT chip reportedly exhibited failures in which the GPU die would detach from the chip carrier, or the chip would detach from the logic board. Apple initially ignored reports, before admitting to the fault and replacing logic boards free of charge for up to 4 years after the purchase date. NVIDIA also confirmed the issue, and previously manufactured replacement GPUs,