The CR Lithium battery is a 3 volt, non-rechargeable battery. CR Lithiums are often used in the following applications: car starters, garage door openers, and computer memory back, just to name a few. There is little doubt that you have CR Lithium batteries in some or even many, of the consumer electronic devices you use every day.
Size : 2016 - 20*1.6mm
2032 - 20*3.2mm
So if you need more than 3V in 20*3.2mm area, two of those 2016s will do the job
Capacity: 2016 - 90mAhr typical
Usage : 2016 - widely used in watches due to the fact that this cells are slim.