tape measure 
noun
A length of tape or thin flexible metal, marked at graded intervals for measuring.Use a steel tape measure to measure the length of your frame on both sides of the door and across the top....
- A flexible tape measure is the only tool to accurately measure the human body's curves and contours.
- Suddenly when I wasn't looking (my gaze had drifted over to the lingerie section) he had whipped his tape measure out and measured my waist!