Fine emery (a black silicon carbide) is glue-bonded onto a very thin, paper backed 3/4", Snap-On Discs. Cutting face on one side only. Economical and great for cleanup and finishing. Not recommended for use with Gold or Amalgams, this type of abrasive is excellent on most other metals (precious and non-precious) as well as enamel and porcelain. A great general purpose choice. Sold in boxes of 200 discs. These discs have the Moore Snap-on brass center so they need to be used with a Snap-on mandrel (see 840-3200, sold separately).