This CFII PTS Study Guide is a very thorough explanation of all of the CFII PTS sections. It is packed with detailed text and graphics explaining each element required during the checkride in detail. Colorful graphics show exactly how systems, intruments, navigational aids, etc... function.
The study guide is over 140 pages of packed information that brings text and graphics from current FAA handbooks and relevant material to the guide instead of having to reference multiple books while studying. Although it is definitely a self sufficient study guide, all material is referenced including many hyperlinks so you can quickly reference the source.