A newly passed law in California restricts sales of a popular type of handgun that critics have long said is too easy to convert into a machine gun.

The law, signed by Gov. Gavin Newsom on Oct. 10, will outlaw retail sales of semiautomatic handguns that can be easily modified using a category of tools commonly known as "Glock switches" – machine gun-conversion devices that interfere with the gun's trigger device to allow shots to continually fire while the trigger is pressed.

The law comes after years of criticism and litigation aimed at Glock for continuing to manufacture guns compatible with the switches. The devices can enable pistols to fire at rates of up to 1,200 rounds per minute, according to gun control advocacy group Everytown for Gun Safety.

In one example last year, a mass shooting in Birmingham, Alabama, that killed four and injured over a dozen involved what officials believed to be Glock switch-modified guns.

The move in California comes as a number of Democratic-led states are looking for their own solutions to the problem of illegal machine gun conversion devices, turning to lawsuits and pondering their own anti-Glock measures in the absence of the company taking steps to thwart the switch devices, said Jennifer Dineen, a professor at the University of Connecticut and member of the Rockefeller Institute of Government’s Regional Gun Violence Research Consortium.