With the passage of Prop 64 in California, the possession of marijuana for recreational purposes became legal for adults aged 21 and older as of January 1, 2018. This includes up to 8 grams of concentrated cannabis — such as wax/dabs, commonly used in dab pens.
If you are caught with a dab pen, what happens will depend on your age and the amount that of concentrated cannabis that is in the pen. If you are under the age of 21, possession of any amount of concentrated cannabis is an infraction. If you are over the age of 21, then possession of more than 8 grams of wax or dabs is a misdemeanor offense, punishable by up to 6 months in county jail and/or a $500 fine.