Marshalltown M722 Blue Steel Scarifier 8� The Marshalltown M722 scarifier isused for scratching the plasterundercoat to create better bonds between layers. The tines have been heat-treated for maximum strength and durability. Features: 3� x ��flexible blued steel blade to scratch plaster undercoat - allows the second coat of plaster to grip better 75mm longtines that have been heat-treated for long life Aluminium Backer Plate Specification: Length: 8"/203mm