Central Meridian: Straight line half as long as the Equator.
Other Meridians: Equally spaced sinusoidal curves intersecting at the poles and concave toward the central meridian.
Parallels: Unequally spaced straight parallel lines, perpendicular to the central meridian. Spacing is widest near the Equator.
Poles: Lines one-third as long as the Equator.
Symmetry: About the central meridian or the Equator.
This projection is equal-area. Scale is true along the 55º51' parallels and is constant along any parallel and between any pair of parallels equidistant from the Equator. It is free of distortion only at the two points where the central meridian intersects the 55º51' parallels. This projection is not conformal or equidistant.
For this projection, only one standard parallel is specified. The other standard parallel is the same latitude with the opposite sign. The standard parallel is by definition fixed at 55º51'.