Overall height is .265" and width is .188". It is important to measure the key in the crank to see how far it sticks out then measure the depth in the gear before installing to make sure the key is set to the correct depth.
Different gear manufactures have different depths in the gear. Keys are sold individual. RCD gears use a cut down key due to the distance of the root of the tooth to the woodruff key slot on some of the gears get thin and it is a weak area for the gear to break in.