It is 6.8mm in diameter and 2.1mm high.
Datasheet: ML-621S/ZTN datasheet
Material safety datasheet : ML-621S/ZTN msds
**If you require Air (overnight) shipping, these batteries must ship as Class 9 Hazardous or Dangerous Goods. There will be an additional fee of $75.00 to cover the Hazmat Surcharge, and you will be contacted for payment after ordering. (PLEASE NOTE - there is no extra charge for ground transport)**