The first step towards a safer-to-use razor was the guard razor – also called a straight safety razor – which added a protective guard to a regular straight razor. The first such razor was most likely invented by a French cutler Jean-Jacques Perret circa 1762. The invention was inspired by the joiner's plane and was essentially a straight razor with its blade surrounded by a wooden sleeve. The earliest razor guards had comb-like teeth and could only be attached to one side of a razor; a reversible guard was one of the first improvements made to guard razors.