The locking device on the proportional dividers allows you to maintain the same proportions on the drawing. Widely used for draiwng, accurate measurement. Suitable for most architects and artists Precisely proportional divider drawing tool is easy to use. Aligns the subject item you want at the small end of the dividing line, and transfer the spacing of the big end to your drawing area Professional proportional divider ensures professional levels accuracy in your drawing and designs, helping you create achieve amazing result Package includes: 1Piece proportional dividers drawing measurement caliper tool. Size: 9.84Inches Our proportional dividers scale artist drawing tool light in weight, easy to grip, wear-resistant, not easy to break, for long time use, Manufacturer: BOYANDM