Standard Backing Pads, 5/8 in – 11, Medium. Standard air-cooled all-purpose. Ideal for sanding operations on metal, plastic, fiberglass, etc. Attributes: Arbor Diam [Nom] = 5/8 in, Dia. [Nom] = 5 in, Face Type = Spiral, Hardness Grade = Medium, Roughness Grade = Medium, Speed [Max] = 10,000 rpm, Thread – TPI or Pitch = 5/8 in – 11, Wt. = 0.14 lb. (1 EACH = 1 EACH)