LENMAR WCCR1616 3-Volt Lithium Coin Battery (CR1616; 57mAh) Fits Texas Instruments(R) TI-73, TI-85, TI-86, TI-89, TI-92, TI-92 Plus; Replaces Panasonic(R) BR1620; Sony(R) CR1616; 3V; 57mAh; Lithium; 30-day warranty