From Wikipedia
The Stevie Ray Vaughan Stratocaster is the signature model electric guitar of American guitarist Stevie Ray Vaughan, based on his favorite guitar, Number One. The guitar debuted at the NAMM Show in January 1992 and began selling at various music stores.
Number One, also called First Wife, was the nickname given by Vaughan to his favorite Fender Stratocaster, built c. 1963. In 1974, he acquired the guitar as a trade at a music store in Austin, Texas. In 1990, it was retired due to many replacements of frets, though he continued to play it occasionally. In 1992, the Stevie Ray Vaughan Stratocaster was released, based on the specifications of Number One. Vaughan used Number One on almost every recording with Double Trouble.