Sew Square 4™ is a 4" x 4" clear acrylic ruler with easy to use black lines and marks. 

Sew Square 4™ has unique marks for squaring-up 4" x 4" units from multiple Sew Kind of Wonderful patterns.  

Patterns that have 4" square-up steps include:

Posh Holiday Series

Wonderful Curves Sampler Book

Floral Felicity Sampler Book

Mini Wonderful Curves  Book

Starry Night

Happy Together

Cool Cars

Sew Square™ rulers can easily be marked with a permanent marker (ie: Sharpie) for other patterns and other square up points. Marks can easily be removed with a little nail polish remover.