Type A (or flat blade attachment plug) is an ungrounded plug with two flat parallel pins.
Type B has two flat parallel pins and a round grounding (or earth) pin.
Type C (or Europlug) is a two-wire plug that has two round pins. It fits into any socket that accepts 4.0 – 4.8 mm round contacts on 19 mm centres.
Type E has two 4.8 mm round pins spaced 19 mm apart and a hole for the socket's male earthing pin.