Colons

A colon (:) can be used to introduce a list or a quotation.

For my holiday I am going to need to pack: sun cream, sunglasses, a towel and a sun hat.

In the novel ‘Of Mice and Men’ the writer suggests Lennie’s animalistic qualities when he says: “Lennie dabbled his big paw in the water.”

A colon can also be used to introduce examples or explanations. The part of the sentence after the colon gives a little more information about what comes before it.

It is a big house: there are six bedrooms all with their own bathroom.

Rabbits are very furry: they need to keep warm in the winter.

http://www.oxforddictionaries.com/words/punctuation