LENMAR WCCR1620 3-Volt Lithium Coin Battery (CR1620; 75mAh) Fits Texas Instruments(R) TI-73, TI-85, TI-86, TI-89, TI-92, TI-92 Plus; Replaces Panasonic(R) BR1620; 3V; 75mAh; Lithium; 30-day warranty