Tactile biofeedback reference attachment

A tactile reference attachment comprising:

• a flexible, elastic, and water resistant primary substrate having a plurality of attachment perimeter edges, a substrate exterior surface, a substrate interior surface, an adhesive on one of the substrate exterior surface and the substrate interior surface, a primary substrate thickness of no more than 4 mm, and at least a tactile reference indentation having a plurality of indentation perimeter edges, a tactile reference longitudinal axis, a tactile reference indentation width of no greater than 5.0 millimeters, a tactile reference indentation depth of 0.5-4.0 millimeters, and a tactile reference indentation length that is at least five times the tactile reference indentation width;
• wherein at least two of the plurality of indentation perimeter edges are separated from the nearest attachment perimeter edge by an edge clearance distance, and the smallest edge clearance distance is at least 50% greater than the tactile reference indentation width;
• and
• wherein the primary substrate thickness is at least 25% greater than the tactile reference indentation depth but no more than twice the tactile reference projection width.

A tactile reference attachment comprising:

• a flexible primary substrate having a plurality of attachment perimeter edges, a substrate exterior surface having an adhesive, a substrate interior surface, a primary substrate thickness of 0.75-4 mm, and at least a tactile reference projection having a plurality of projection perimeter edges, a tactile reference longitudinal axis, a tactile reference projection width of no greater than 5.0 millimeters, a tactile reference projection height of 0.5-4.0 millimeters and no greater than the tactile reference projection width, and a tactile reference projection length that is at least five times the tactile reference projection width;
• wherein at least two of the plurality of projection perimeter edges are separated from the nearest attachment perimeter edge by an edge clearance distance, and the smallest edge clearance distance is at least 50% greater than the tactile reference projection width;
• wherein the primary substrate thickness is at least 25% of the tactile reference projection height;
• and
• wherein the tactile reference projection length is at least 25 mm and at least ten times the tactile reference projection width.