The United Healthcare Silver Compass H.S.A. 3600 plan is classified as a HMO (Health Maintenance Organization) plan. HMO plans require members to use in-network providers for all non-emergency care. Members must select an in-network primary care provider (PCP) who coordinates all care and referrals to specialists. Using out-of-network providers typically results in no coverage, except in emergencies. This plan's network structure and requirement to designate a PCP are characteristics of an HMO plan.