Maine instituted gun control measures Friday, including a 72-hour waiting period for buying guns, one year after the state’s deadliest mass shooting.

State leaders have clamored to put into place gun control measures after Army reservist Robert Card murdered 18 people with a rifle in the tenth-deadliest mass shooting in United States history. One approved policy pushed by activists was a waiting period, requiring customers to wait 72 hours after purchasing a firearm to obtain it.