Most commonly steamer clams are the type of clams used for steamers because they have soft and brittle shells and do not completely close since the long neck or siphon gets in the way.
However sometimes other clams such as Littleneck clams or cherrystone clams are used as a substitute for steamer clams to make steamers.
But if you want the best dish for clams you should use the steamers.
Steamer clams are also used for New England's famous fried clams.
The steamer clams are also known as soft shell clams and have a small neck like siphon sticking out between their shells.
The shells aren't really soft though but it's just called that.