A measuring tape is a ribbon of cloth, plastic, or metal with linear-measure markings, often in both imperial and metric units. Measuring tapes are available in different lengths. The shorter tapes are usually made with a curved cross section, so they are flexible enough to roll up but stay rigid when they are extended. When using a long, flat tape, lay it along a surface to keep it from sagging in the middle.
Steel measuring tapes are usually wound into metal cases. A hook at the end of the tape hooks over the object you are measuring. The tape may have a lock that holds the blade open and a rewind spring that returns the blade to the case. Look for a tape that is easy to read. Good-quality tapes have a polyester film bonded to the steel blade to guard against wear.