A Philippine visa is an endorsement by a consular officer on a travel document (e.g. passport) denoting that the visa application has been examined, and that permission is requested from Philippine immigration authorities at ports of entry to allow the bearer to enter and stay in the Philippines for a specified period of time. A visa is not a guarantee that the holder will be automatically admitted into the country as admission of foreign nationals into the Philippines is a function of the Bureau of Immigration. Philippine visa holders are, therefore, subject to regular and discretionary immigration control at ports of entry. The Bureau of Immigration may deny entry of any visa holder for any valid reason.