420 is a number associated with marijuana, also known as cannabis or pot. This came about in the early 1970s in San Rafael and is now a very widely used term in the marijuana industry. 420 is a popular term and it is even associated with a day, 4/20, which celebrates marijuana.

prop64 explanation of proposition 64 mmjdoctor

CALIFORNIA WEED LAWS-EXPLANATION OF PROP 64 (UPDATED 2019)

California Marijuana Law, Health & News, MMJ California
  Despite the federal government regarding marijuana as a schedule 1 drug, California, on November 8th, 2016, voted for the recreational use of pot. This is not to mean that you can walk around smoking weed in the streets. No, there…