Evaluation of Experimental and Commercial Air-Activated, Adhesive Backed Heat Patches

Inclusion Criteria: * Participants are 18 to 70 years of age; * must be in general good health; * must have absence of any visible disease that might be confused with a skin reaction to the test material; * back region must be free from excessive hair, cuts, tatoos, or other aberrations; * must understand and sign Informed Consent; * must be considered dependable and able to follow directions; * Participants assigned to the thermocouples must be willing to restrict their activity for the 8 hour patch wear time so that the thermocouples do not come loose; * Participants assigned to the thermocouples must be willing to wear a pouch containing the thermostat and thermocouple wiring for the entire 8 hour period and to return all study supplies to the site at visit 15. If the items are not returned subject may be invoiced for the value of the unit; * must be willing to not wear any topical products such as lotions, sunscreens, etc. in the test area while participating in the study; * must agree to use an adequate means of birth control which include: abstinence, partner vasectomy, Intrauterine Device, hormonal implant devices/injections, regular use of birth control pills, birth control patches or condoms with a spermicidal agent; * Participants are willing to come in each day with a CLEAN back; * Participants who are 55 years of age and older, agree to supply a t-shirt to wear at visit two that can be marked on with a marker, and to use that t-shirt or supply others at the morning visits (visits 4, 6, 8, 10, 12, 14). Exclusion Criteria: * Participants with known skin sensitivity to adhesion products; * Participants with any skin abnormality likely to be aggravated by the study material such as dermatological disease or infection, rash, atrophic, fragile, or abnormally dry skin, cuts or abrasions at the treatment site; * Participants who are pregnant or nursing, oral interview only; * Participants with diabetes or poor circulation; * Participants unable to tolerate conditions of protocol; * Participants viewed by the investigator as not being suitable for the study; * Participants who have had active skin cancer including basal cell carcinoma, or other cancer within one year; * Participants who are currently participating in another clinical trial; * Participants who routinely use anti-inflammatory medications (within 5 days of study start (81mg aspirin is okay)) or immunosuppressive or antihistamine medications within 3 weeks prior to study start (steroid nose/eye drops are ok); * Participants who currently use allergy injections; * Participants with history of severe asthma; * Participants with active or uncontrolled immunologic disorders i.e. AIDS, HIV positive, systemic lupus erythematosus, rheumatoid arthritis; * Participants with uncontrolled thyroid disease; * Participants who have any clinically significant chronic illness which could place the subject at increased risk during participation or result in inappropriate dermal response during the study; * Participants who have used topical medications at the test sites within the past 14 days; * Participants who have lower midline abdominal pinnicula which may interfere with heat patch/wrap application and or evaluation; * Participants who have a pacemaker, defibrillator or other implantable medical device; * Participants who have allergies to latex, polyethylene, polypropylene, nickel, chromium or aluminum.