Whereas older instruments fitted with valve attachments usually had the tubing coiled rather tightly in the bell section ("closed wrap " or "traditional wrap"), modern instruments usually have the tubing kept as free as possible of tight bends in the tubing ("open wrap"), resulting in a freer response with the valve attachment tubing engaged. While open-wrap tubing does offer a more open sound, the tubing sticks out from behind the bell and is more vulnerable to damage. For that reason, closed-wrap tubing remains more popular in trombones used in marching bands or other ensembles where the trombone may be more prone to damage.