A health savings account or flexible savings account can help you pay for qualified medical costs, but that doesn't just mean doctors' visits or medications. "They're also a powerful way to pay for a huge range of modern wellness technology and products," said Chris Byrd, senior vice president at WEX, a global commerce platform that administers HSAs and FSAs. According to Byrd, recent research from WEX and Visa found that having the flexibility to use HSA funds on qualified expenses was one of the top motivators for people to contribute to an HSA. "This trend is transforming how employees view their benefits, as these accounts aren't just for emergencies anymore," explains Byrd. Don't miss any of our unbiased tech content and lab-based reviews. Add CNET as a preferred Google source. These are some unexpected wellness tech products that may be covered by your flexible or health savings account. Just note that you should check for eligibility beforehand and that some items may only be eligible based on medical need, meaning you'll need a letter from your doctor. 1. Massage guns You may be surprised to learn that massage guns like Therabody's Theraguns could be FSA- or HSA-eligible. Starting at $200, you can also find two massage guns from the brand Caring Mill by Aura, an in-house brand from the HSA and FSA Stores, that could be eligible. One is even heated and comes in a two-pack. There's also a vibrating, heated foam roller and Therabody's TheraCup for cupping therapy paired with heat and vibration. 2. Oura Ring The Oura Ring can be bought using funds from your FSA or HSA. Caroline Igo/CNET The Oura Ring, CNET's favorite smart ring, is now FSA- and HSA-eligible. You can place an order through Oura Ring using your FSA or HSA card, or later submit your purchase for reimbursement. 3. Whoop wearable Our best overall sleep tracker is the Whoop 4.0, and we recently reviewed the Whoop 5.0, which we like for its healthspan and hormonal insights. On the FSA and HSA Stores, your Whoop 5.0 purchase also comes with the SuperKnit band, a 12-month membership, a waterproof Wireless PowerPack and a lifetime warranty. 4. Smart blood pressure monitors Blood pressure monitors are available in the HSA and FSA Stores. Miljan Živković/Getty Images Garmin's Index BPM Smart Blood Pressure Monitor is available for $200. It has built-in Bluetooth and Wi-Fi and can be connected to your smartphone via the Garmin Connect app. At a more affordable $76, there's also the OMRON Evolv Wireless Upper Arm Blood Pressure Monitor, which connects to smart devices via an app to help you track your blood pressure readings. 5. Chest strap heart rate monitors CNET's pick for the best chest strap heart-rate monitor with the best battery life is the Garmin HRM-Pro Plus Chest Strap Heart Rate Monitor, which is HSA and FSA-eligible. It can connect to your smartphone, Garmin watch or another compatible fitness device to provide real-time heart rate data. For $50 less, you can also get the Garmin Heart Rate Monitor 200. 6. Light therapy devices A red light therapy LED mask may be covered by your FSA or HSA. Dr. Dennis Gross Whether you're looking for a red light therapy LED mask like that from Dr. Dennis Gross or a panel such as the one offered from reVive for your skin-care routine, you may be able to get one covered using your HSA or FSA. 7. Compression boots Also listed on the HSA and FSA Stores are the Therabody JetBoots, compression boots that reduce muscle pain, increase blood flow and promote recovery. The JetBoots Prime is $600, and the JetBoots Pro Plus is $1,200, and they also come with vibration and red light therapy. But first, make sure your items are eligible Byrd explains that it's important to pay attention to the fine print and requirements for HSA or FSA eligibility. "Broadly speaking, eligibility is tied to use for treatment of a medical condition," he says. "If the item or service is for general health and well-being or cosmetic reasons, it's typically not going to be eligible. Items like the Theragun and acne masks fall into this category, where they are HSA eligible, conditioned on medical need. In such cases, a note from a medical practitioner, commonly known as a letter of medical necessity, is normally required." To ensure an item is HSA-eligible, consult your HSA provider's online dashboard or app. What's the difference between an HSA and an FSA? "The main difference is that an HSA is an individually owned account," says Byrd. "It can be set up through an employer plan or individually at the HSA provider of your choice. It stays with you, even if you change jobs, while an FSA is tied to your employer and often has a 'use-it-or-lose-it' rule at the end of the plan year." Those participating in an HSA must be enrolled in an HSA-qualified health insurance plan, while FSAs work with any group health insurance plan. "Another key difference that people may not realize is that they can invest HSA funds, but not FSA funds," adds Byrd. Depending on your provider, you may be able to invest your HSA funds into mutual or index funds, so your money can grow tax-free over time for future healthcare expenses.