METRC is the system used by the cannabis industry as a "secure database to track and trace cannabis from growth, harvest, and processing to testing, transport, and sale" as mandated by governing entities. * METRC monitors the cannabis supply chain and keeps track of every transaction that takes place. All cannabis license holders must enter their transactions into METRC when cannabis products are produced or change hands from license holder to license holder. "Every cannabis plant and every cannabis product is accounted for by licensed businesses in Metrc’s system."*

Basically this is the system all cannabis license holders must use to track inventory and sales. The idea is to protect public health and secure the marketplace against illicit product.