Synchronized Tremolo

i meant to say compress and depress the STRINGS like a floating trem.

A tremolo arm, tremolo bar, vibrato bar, whammy bar the synchronized tremolo moves the bridge as well as the tailpiece, varying both the length and tension of the strings.

i meant to say compress and depress the STRINGS like a floating trem.

Only if set up to do both up and down. The original Synchronized Trem was created and set up only to bend downward, as the trem springs were adjusted to pull the bridge plate flat against the body. Despite loss of up-bending, this has advantages: more stable tuning, and remaining strings will stay mostly in tune if one breaks.

At some point, someone realized a Synchronous Trem could be floated to allow both up and down bends. That requires more careful setup, such as attention to the condition of the six pivot screws in order to work smoothly and return to pitch consistently, but it is done more often than not these days.

So if you trem is set up with the bridge plate jammed flat against the body, it is set up in vintage fashion to do down bends only. If the bridge plate is "floating" at an angle off the guitar body, then it is set up for up and down bends. You can have either depending upon setup. But when converting from one to the other, careful trem spring adjustment and re-intonation is required. If you don't know what to do, then take it to a guitar tech.