What is the difference between an invention patent and a utility model patent?

There are four features that distinguishes a utility model patent from an invention patent:

1. a utility model patent has a shorter life span than an invention patent;

2. the standard of a utility model patent is lower than that of an invention patent;

3. a utility model patent is not given a "substantive" examination by the relevant national Patent Office; and

4. a utility model patent costs less than an invention patent.