Stretchable strands for fabric items

A stretchable layer of fabric for attaching an electronic device to a user's body, comprising:

• a first set of strands;
• and
• a second set of strands intertwined with the first set of strands, wherein at least one of the first and second sets of strands includes a stretchable strand comprising:
• an elastic core,
• a first layer of material surrounding the elastic core, and
• a second layer of material surrounding the first layer of material and the elastic core, wherein the first layer of material has a greater thickness than the elastic core, wherein the stretchable strand has a volume defined by the elastic core, the first layer of material, and the second layer of material, and wherein the first layer of material consumes more of the volume than the elastic core and more of the volume than the second layer of material.

A strap configured to attach an electronic device to a user's body, comprising:

• stretchable fabric formed from stretchable intertwined strands, wherein the stretchable intertwined strands each comprise:
• a core formed from a single elastic strand,
• a first strand twisted around the core, and
• a second strand twisted around the first strand and the core, wherein the first and second strands form a covering having a thickness that is greater than a diameter of the core, wherein each of the stretchable intertwined strands has a volume defined by the core, the first strand, and the second strand, and wherein the first strand consumes more of the volume than the core and more of the volume than the second strand.