Colorado public school teachers are on the lookout for students who are using devices in class to hide the smell and smoke of marijuana.
Some students are using vapor pens, which are just like e-cigarettes. The can be purchased $25. When used for marijuana there's no unusual smell, which makes it easy for students to bring them to school.
According to KCNC-TV, teachers are told to keep a special eye out for students who appear to be biting their pens.
Lakewood High School campus security supervisor Tim Martinez says students can use the pens to smoke marijuana and hash oil.