Prym OmniGrid Ruler
The Metric Metric Omnigrid Ruler is a neat and portable way to help cut your fabric to size.
It also has a 7 1/2cm x 7 1/2cm grid in one corner.
Made with contrasting yellow and black lines allow the grid to be seen on light or dark fabrics. The heavy duty acrylic allows large rotary cutters to cut multiple layers of fabric at a time.