Texas Instruments Slide Cover Case for TI-83 Plus TI-83 TI-86 TI-89 Calculator
Amazon lists the TI-83 slide cover as fitting the TI-83 Plus, TI-83, TI-86, and TI-89. TI-89 (original, not Titanium). TI-89 Titanium (different body than original TI-89). TI-84 Plus (different body style).