This is a Cook Islands 1932 stamp.  It is SG 102, the 2 1/2d Black & Blue.

The thing to note about this little beauty is that the CENTER IS INVERTED!  This is a stunning error!  See the SG footnotes for more information about it.

The stamp is in unmounted Mint Very Fine Condition and has its lower margin!

This item is over $100 USD so I will be shipping it using Priority Mail in the US, and Registered Mail overseas.  This is to ensure that it reaches you in a safe and timely manner, and includes tracking!