Compared to the 5-15P plug, the 5-20P plug has the neutral blade rotated 90° and shifted so its inner edge is approximately from the hot blade. The 5-20R receptacle has a T-shaped neutral hole, to accept both 5-15P and 5-20P plugs. An acceptable alternative version of the 5-20R receptacle has a rectangular slot that will only accept 5-20P plugs. The 5-30 and 5-50 are physically larger, with between power pins; 5-30 also has an L-shaped neutral blade. These larger sizes are uncommon, as twist-locking plugs are generally used for high-current applications.