PROVISIONAL PATENT INFORMATION
A provisional patent application is somewhat similar to a utility patent application in that it has a description and drawings, and differs in that it needs no claims (but may have claims). The provisional patent application is not examined. It is filed, is good for one year, and never becomes an issued patent. The provisional establishes an early filing date for priority purposes. In the event of an interference later, or in the course of normal prosecution, you can use the provisional to "swear behind" a reference.
Within one year, you must file your regular utility patent application, in order to claim the priority date. The utility case will then have an effective filing date of the provisional. Any foreign applications must also be filed within one year of your provisional, or you lose the right to file foreign.
The provisional patent application is less expensive than a regular utility case, and so it saves some money and buys some time. However, since it is not examined by the Patent Office, you don't know if your utility patent claims will be allowed. You also don't know, in a timely manner, if your expensive foreign applications will be allowed. The value of a provisional application is to test market the invention without incurring the expense of a regular application.