The standard voltage: 220V, frequency 50Hz.
Plug type: D, M, G and F.
Type D: mainly used in India, Sri Lanka, Nepal, and some African countries. This socket only works with plug D.
Type M: looks like plug D, but with larger pins. This socket only works with plug M.
Type G: this type is of British origin. This socket only works with plug G. Type F: also known as "Schuko". This socket also works with plug C and plug E.