Bias Ruler 28in x 2.5in from TQM Rulers.
This item helps quilters to cut bias strips for binding, applique (Stems & Vines), piping, or for making your own bias strips.
This is the UK version that is designed to fit on a half metre of fabric, rather than a half yard. It folds up so you can store it away or take it with you.
Watch the video here.