The User’s Review: Canon EOS Rebel X and XS (EOS 500), both released in 1993
Both in light weight, the compact Rebel X and XS cameras are different by the two lights, flash and AF-assistant lights on XS only. Therefore, there is one extra button besides the self timer on SX to control the flash.
It said that S in the model code represents flash. Maybe should include the AF light also.
EOS 500 marketed in other parts of the world is another name of X s.