The back would have only 4 tabs.

___ ___
___ ___


2 in the middle of the switch and 2 on one end of the switch. Double throw would have 6 tabs or screws.

Off would be in the middle, on would be either left or right, up or down.

 

Dual pole means = two circuts or switches

Single throw means only one position change.

So as CC said , 4 connections at back, two inputs and correspondingly 2 outputs. You can switch two completely separate circuts at same time, or one circut with higher power by ganging the two poles (connecting them together)