PROPORTIONAL SCALE DIVIDER: Trasfer measurements from live subjects, photographs or sketches to acheive accurate proportions and perspective in your finished artwork. Scales in ratios from 5:1 to 1:5. PERFECT DRAWING OR PAINTING TOOL: This proportional divider is not just for architects and engineers. It's an extremely good option for artists. And it is quite useful for that people who are frequently paint or draw from a reference that requires size reduction or enlargement. EASY TO USE: Simply sight your subject with the upper tips at arm's length and use the bottom points to in perfect proportion. Takes guesswork out of drawing anywhere at anytime. PREMIUM DESIGN: Made of strong plastic, it takes constant use and handling. 10 inches long. The different holes allow a scene to be accurately scaled up or down in size while maintaining proportions. TIPS: Gently place the proportional dividers against the drawing paper or canvass to prevent moving the legs. Even the slightest movement creates inaccuracies in the scale. Always measure objects with a proportional divider with your arm fully extended to keep your measuring . Easy to use: Step 1: Slide the locking clip up and down to adjust the scale, move the green tab towards the middle of the divider to reduce the size. Move the green tab towards to enlarge the size. : Hold the proportional divider with one hand and extend your arm out directly in front of you. , put the item you to draw within of the small opening of the proportional divider. Adjust the dividers with one hand until the two needle points on the short end accurately the dimensions of the object from your vantage point. Step 3: Bring the proportional dividers back to your drawing paper or canvas and use a pencil to the length created by the larger opening of the divider. Since the proportional divider operates on a pivot, the small opening and the opening are proportional to each other. Thus, even though you measured the object with the small opening, the opening transfers the measurement to a larger scale. Step 4: Continue measuring objects with the small opening of the proportional dividers and transferring the scaled measurement to the drawing paper. Use these measurements to draw a proportional illustration. Colour: black Material: plastic Size: length of about 25.5cm Package Contents: 1 * Proportional Divider Drawing Tool 3 * Locking clip(Red, green, blue) Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.