The purpose of this subpart is to implement section 721 of the National Defense Authorization Act for 1999, Public Law 105-261. This section amended chapter 55 of title 10, United States Code, and chapter 89 of title 5, United States Code, to establish a demonstration project under which certain Medicare and other eligible Department of Defense (DoD) beneficiaries can enroll in health benefit plans offered under the Federal Employees Health Benefits (FEHB) Program in certain geographic areas. The legislation was signed into law on October 17, 1998. The demonstration project will run for a period of three years. The legislation requires the Office of Personnel Management (OPM) and DoD to jointly produce and submit two reports to Congress designed to assess the viability of expanding access to the FEHB Program to certain Medicare and other eligible DoD beneficiaries permanently. OPM is authorizing certain differences from regular FEHB Program practices in order to ensure the successful implementation of the demonstration project. This regulation authorizes those differences.