The Renata Battery 1620 is a must-have battery, suited for most devices and gadgets that make use of button sized batteries. These include most makes of watches from trusted brands, calculators, digital meters, medical equipment like glucometer etc.; these batteries are 3 V lithium batteries. Being Swiss made, they ensure the use of excellent material, which vouches for the overall quality of the cells. These are designed to supply constant power to the device they are being used with.