These scratch brushes have pen shaped handles and come in 4 different types. They are used for removing rust or corrosion in hard to reach places. The brass model is excellent for cleaning clogged burs. The metal ferrules are for improved durability. Refills are packaged 24 to a box. Length is 4-1/2", refills are 1-1/4" long. Except for the economy fiberglass brush (which is made in India), all these scratch brushes are made in Germany.