Medicare Supplement Insurance, also known as Medigap, is designed to cover the 20% of healthcare costs not covered by regular Medicare, allowing beneficiaries to see any doctor nationwide who accepts Medicare. These plans, identified by letters A through N, offer consistent basic benefits across different providers, though they vary in cost and additional coverage. Medigap does not include Part D Prescription Plans. It's advisable to reassess your Medigap plan every 2-3 years to ensure competitive premium rates. For more details, contact CSG Medicare to determine if this coverage meets your needs.