The Lyra Groove Triangular Colouring Pencils are ergonomic and triangular in shape a great quality product for all ages.Ergonomic triangular shape with 10 mm diameter.Natural grip zone with no additional artificial materials.Offset slide guards for thumb index and middle fingers to support an optimal writing hold - even after sharpening.Extra break-resistant colour-intensive 4.25 mm lead.For left and right-handers.With name field.