Medicare Supplement Plan K, also known as Medigap Plan K, offers lower premiums while covering preventive services and providing an additional year of hospital coverage. However, you share the cost of many other benefits, including the Part A deductible, and you are fully responsible for the Part B deductible and any excess charges. One of the key advantages of Plan K is its annual out-of-pocket maximum. Once you reach that limit, the plan pays 100% of your covered medical expenses for the remainder of the year.