We've had several customers use FSAs (Flexible Spending Accounts) and HSAs (Health Savings Account) to purchase Iron Neck and Fitness Bundles from us, so it's definitely an option. FSA and HSA insurance programs are governed by IRS guidance and allow the ability to apply these funds toward medical expenses, as authorized by category guidance and physician approval. A primary difference between FSAs and HSAs is that the individual controls an HSA and allows contributions to roll over, while FSAs are less flexible and are owned by the employer.
This is according to an IRS publication regarding what they consider as legitimate medical expenses: "Medical expenses are the costs of diagnosis, cure, mitigation, treatment, or prevention of disease, and the costs for treatments affecting any part or function of the body. These expenses include payments for legal medical services rendered by physicians, surgeons, dentists, and other medical practitioners. They include the costs of equipment, supplies, and diagnostic devices needed for these purposes. Medical care expenses must be primarily to alleviate or prevent a physical or mental disability or illness. They don't include expenses that are merely beneficial to general health, such as vitamins or a vacation."
If you are purchasing Iron Neck equipment specifically to treat, prevent, or rehabilitate an injury, then you are following the intent of the IRS and should be good to spend FSA or HSA funds. Fitness and rehabilitation equipment fall into an FSA approved category but often requires a letter from a physician (primary care, physical therapist, or chiropractor) to verify the expense is appropriate.