A handheld computing device and handheld music player are disclosed. The handheld computing device includes a seamless enclosure formed from an extruded tube. The extruded tube includes open ends and internal rails which serve as a guide for slidably assembling an operational assembly through the open ends of the extruded tube, a reference surface for positioning the operational assembly relative to an access opening in the seamless enclosure, and a support structure for supporting the operational assembly during use. The handheld music player includes an elongated extruded tube extending along a longitudinal axis. The elongated extruded tube has a first open end and a second open end opposite the first open end, and defines an internal lumen which is sized and dimensioned for slidable receipt of operational components of the handheld music player. The lumen includes rails for guiding the operational components to their desired position within the lumen.