Type B is used, for instance, in North and Central America and Japan.
This class I plug is designated as American standard NEMA 5-15. It has two flat 1.5 mm thick blades, spaced 12.7 mm apart, measuring 15.9 – 18.3 mm in length and 6.3 mm in width. It also has a 4.8 mm diameter round or U-shaped earth pin, which is 3.2 mm longer than the two flat blades, so the device is grounded before the power is connected. The centre-to-centre distance between the grounding pin and the middle of the imaginary line connecting the two power blades is 11.9 mm. The plug is rated at 15 amps.
In some parts of Central and South America, grounded type B outlets are still rather uncommon. Therefore people often simply cut off the earth pin of a type B plug in order to mate it with a two-pole ungrounded socket.
Type A and B plugs are not insulated (i.e. the pin shanks do not have a black covering towards the plug body like type C, G, I, L or N plugs) and the outlets are not recessed into the wall, which means that if a the plug is pulled halfway out, its prongs are still connected to the socket. Type A and B sockets are potentially dangerous, since the distance between the receptacle and a partially pulled-out plug is big enough to touch the pins with your fingers or with a metal object such as a teaspoon.