Thermal lead on the original unibody MacBook Pros.

The unibody MacBook Pro debuted in October 2008 in 13- and 15-inch variants, with a 17-inch variant added in January 2009. Known as the “unibody” model because its case was machined from a single piece of aluminum, it had a thinner flush display, a redesigned trackpad whose entire surface was a single clickable button, and a redesigned keyboard. Updates brought Intel Core i5 and i7 processors and introduced Intel’s Thunderbolt technology