BEMCheckBox is an open source UI component from Boris-Em allowing you to implement highly customizable animated checkbox’s within your iOS apps.
With BEMCheckBox you can change the shape of the checkbox (circle or square), you can also customize the size and coloring, and there are six different animations to choose from in how the checkbox animates when checked/unchecked.
This image from the readme shows BEMCheckBox in action:
You can find BEMCheckBox on Github here.
A great checkbox component.