Australian health funds can be either 'for profit' including Bupa and nib; 'mutual' including Australian Unity; or 'non-profit' including GMHBA, HCF and the HBF Health Insurance. Some, such as Police Health, have membership restricted to particular groups, but the majority have open membership. Membership to most health funds is now also available through comparison websites. These comparison sites operate on a commission-basis by agreement with their participating health funds. The Private Health Insurance Ombudsman also operates a free website that allows consumers to search for and compare private health insurers' products, which includes information on price and level of cover.