An electronic device includes a first device housing and a second device housing that are slidable relative to each other. A flexible display spans a major surface of the electronic device. A strap can be attached to the electronic device so as to span a second major surface of the electronic device, where sliding the first device housing toward the second device housing changes the perimeter of an arm insertion aperture defined by the strap and device housings. A deformable device housing arm can extend between the device housing(s) and the strap and can wrap around a user's arm. The first device housing and second device housing can be manufactured from a flexible material to wrap around an arm allowing a first coupler coupled to the first device housing to attach to a second coupler coupled to the second device housing.