The Skidmore Guide to Writing

Colons (:)

Use a colon at the end of an independent clause to introduce a list, an explanation of the clause, or an example:

There are many interesting things in Billy's closet: old shoes, fluffy pompoms, and hundreds of baseball cards.

Don't use a colon after a verb or a phrase like "such as" or "consisting of" or after a form of "to be" (am, is, are, was, were).

Click here to read more about colons in the context of correct grammar.