". Other subtle changes were also made to the guitars over the years, but the basic shape and features of the Strat have remained unchanged. In the 1970s and 1980s, some guitarists began modifying their Stratocasters with humbucking pickups, especially in the bridge position, to create what became known as a "Fat Strat". This was intended to provide a thicker tone preferred in the heavier styles of hard rock and heavy metal. The popularity of this modification grew and eventually Fender began manufacturing models with a bridge humbucker option (HSS), denoted and separated from the original triple single coil by the title of "Fat Strat", as a reference to the humbucker's distinct sound, as well as models with dual humbuckers (HH), better known as "Double Fat Strats". Fender also started making
Stratocaster pickguards specially designed for guitar bodies routed for HSH (humbucker-single-humbucker) and HHH (humbucker-humbucker-humbucker) pickup configurations.
Since 1998, many high-end US-made Fender Stratocasters such as the American Deluxe, American, Hot Rodded American, American Special and American Standard series came with an HSH pickup rout instead of a "swimming pool" (or "bath tub") cavity to increase the total amount of wood that actually can resonate, producing a more complex tone. The HSH rout allows players to modify their pickups to the most often seen after-market configurations without re-routing or cutting into their guitar's body, while maintaining more wood than a "swimming pool" rout."