These cutters are specifically designed to work with polymer clay. FEATURES: - Extremely sharp blade of 0.3mm to ensure the cleanest cut and minimal (or none) need for sanding. - Made of PLA, a recyclable plastic - Extremely durable walls to prevent cracking and breaking Size is measured on the longest side. To clean your cutters, use a damp cloth or a wet tissue. Not dishwasher safe. Do not bake/heat/expose to high temperatures.