Supra Drive Belt Tensioner
Genuine OEM Toyota Drive Belt Tensioner (suit all 2JZ engines with dampening system, like that found on the 6 speed Supra).
Drive belt tensioner maintains the appropriate amount of force on the serpentine/drive belt to keep it tight whilst operating.
It also compensates for any wear/slack in the belt that occurs over time, as well dampening loads on the belt when cycling accessories on/off i.e. AC.