The construction consists of a box, and the tape measure (usually flexible steel banding) is rolled up inside the box. The retraction mechanism allows the tape to be pulled out to the desired length, and then it will retract back to the case automaticallly if released from your grip. | The construction consists of a box, and the tape measure (usually flexible steel banding) is rolled up inside the box. The retraction mechanism allows the tape to be pulled out to the desired length, and then it will retract back to the case automaticallly if released from your grip. |