Eolos is an effective external training device designed to specifically train the inspiratory and expiratory muscles in one same breathing action. These muscles include: diaphragm, abdominals, laterals, oblique. Numerous research studies agree on the benefits of localized breathing training to strengthen the respiratory muscles and achieve greater lung capacity. THE BEST PRICE-QUALITY RATIO. Quality does not have to cost a fortune. Other similar products are either heavily price tagged or market themselves as the least expensive option. In our case we think that our customers deserve a high quality product without the unnecessary add-ons and which delivers results. Eolos offers long lasting quality + comfort + user-friendliness + 1 year guarantee + fast & effective results at an affordable price. HIGH QUALITY ALL THE WAY. We exclusively use advanced quality medical grade plastic to manufacture of Eolos. This is the same material used for medical devices meeting the most stringent requirements. The regulator is 100% rust proof and of excellent toughness against hits and scratches. Eolos is also a pharmaceutical-free product. ONE TIME INVESTMENT ONLY. We don't believe there is a need for respiratory training product lines or additional accessories, when we can offer you one same product which delivers effective results whether your are into sports, performing arts or a respiratory rehab patient. In other words, our philosophy behind Eolos is "one time investment for a product that can effectively meet your needs". ALL-IN-ONE single model with an universal regulator that enables YOU to decide on the resistance level you wish to train at, from very light to the most intense resistance level. This key feature allows you to take total control over your training regime and be able to meet your specific objectives.