# Accordingly, the OPT policy as reflected in this regulation sets forth periods of OPT at three different levels depending on the alien’s H-1B petition status and the alien’s field of study.
* First layer: 12-month for regular OPT that applies to all the F-1 students regardless of their field of study and regardless of their application for change of status to H-1B
* Second layer: 17-month additional OPT only for students of STEM majors which are available regardless of their application for change of status to H-1B
* Third layer: Additional period of so-called “cap gap” through October 1 which is granted to any OPT students regardless of their major field of study but only conditioned upon their filing, selection, and approval of H-1B cap petition.