Medicare Supplement Plan K, or Medigap Plan K, offers low premiums and covers preventive care services and gives you an extra year in the hospital. However, you are required to split the cost of other benefits, including the Part A deductible. You are also fully responsible for the Part B deductible and any excess charges. The advantage of Plan K is that it caps your spending with an out-of-pocket maximum. So, if you reach that cap, Plan K will cover medical expenses for the rest of the year.