Synergy Digital Camera Battery, Compatible with Casio NP-11 Digital Camera, (Li-Pol, 3.7V, 1000mAh) Ultra High Capacity, Replacement for Casio LIS1639CSPC, NP-11, NP-11A Battery - Walmart.com
fx-991EX-PK | CASIO SINGAPORE
POL and REC Functions in Scientific Calculator - YouTube