Medicare Supplement insurance, also known as Medigap or MedSup, is also sold through private insurance companies, but it is not comprehensive medical coverage. Instead, Medigap functions as supplemental coverage to Original Medicare. Current Medigap plans don’t include prescription coverage.
Medigap plans may cover costs like Medicare coinsurance and copayment, deductibles, and emergency medical care while traveling outside the United States. There are 10 standardized plan types in 47 states, each given a lettered designation (Plan G for example) Plans of the same letter offer the same benefits regardless of where you purchase your plan.
You will want to compare the Medigap policies carefully, because while benefits are standardized, the costs are not, meaning they could fluctuate widely depending on the insurance company offering the plan and location.