-MEGA Value Five Pack
-small disc shaped batteries used in everything from calculators to computer memory applications etc
-CR1616 is equivalent to: DL1616, BR1616, KL1616, L1616, ECR1616, KCR1616, E-CR1616 and KECR1616
Got one of those (or 5x) myself for my CASIO watch. Cheapest I could find including delivery. Others start from £3.56 for SINGLE battery.