Plug Type B / NEMA 5-15P

Used in: North and Central America, Japan
The Type B electrical plug has two flat parallel pins and a round grounding (or earth) pin. The earth pin is longer than the other two so that the device is grounded before the power is connected. As with the type A plugs, the American and Japanese versions vary slightly.
Type B plugs are rated at 15 amps.

NEMA standards are used in the US, Canada and Mexico. Comparable flat blade plugs are used in Japan, various Caribbean islands, parts of South America and some Southeast Asian countries
National Electrical Manufacturers Association (U.S.A.)