United's is a book of 4 500 mile certificates good in the US (including Hawaii), Canada, Mexico and Puerto Rico. The cost for Premiers and above is $125 for the book of 4. The General Public pays $200. Premiers can upgrade on ANY published fare. General members of Mileage Plus and the Public can only upgrade on Full fares. Premiers and above receive 1 booklet (4 certs) free for every 10,000 miles flown. Premiers can also purchase these using miles from their account at 30,000 miles for 8 500 mile certs.

[This message has been edited by PremEx (edited 02-14-99).]