PowerBook 520

The PowerBook 500 series was introduced on May 16, 1994, with the high-end active matrix LCD PowerBook 540c and 540, with the passive matrix 520c and 520 soon after. One of its marketing highlights was the promise of a PowerPC upgrade to its CPU and PC Card (PCMCIA) expansion. The introduction of this model came at the time of Apple's changeover to the new PowerPC chip from the 68k line of CPUs, and Apple's advertising and promise of the PowerPC was the cause of headaches to the company.[citation needed] The strong demand for its ground-breaking design and Apple's incorrect market prediction that customers would wait for the fully PowerPC PowerBooks resulted in shortages early on.[3]

Source https://en.wikipedia.org/wiki/PowerBook_500_series