This video gives some historical background to phased conservation and the development of a book wrapper known as a phase box (#phase-box). It then demonstrates one design in common use. There are many designs for phase boxes for different conservation tasks and other construction and usage requirements. The size of the starting piece of card stock is 3xW+2xT-10mm X 3xH+2xT-10mm H Height W Width T Thickness 10mm is about 3/8 inch Because the card stock is thin (about 0.3mm) I don't worry about adjusting the individual side heights of the box. If I was using a thicker materials, especially flutted board, then this would need to be considered.