Perfect for cleaning flat surfaces and getting into hard-to-reach places, the versatile 3/4 In. (19.1 mm) diameter Brass Brushes are ideal for cleaning and surface polishing to create a soft, satin or matte finish. Non-sparking and softer than steel, the brushes are ideal for use on soft metals like gold, bronze, copper or brass. For optimal results, operate the brush at a maximum speed of 15,000 rpm and avoid applying excessive pressure to extend the accessory’s lifespan and performance.