These are made from solid brass rod. The crosshatching and 2° slope on the face help to hold wood securely, pulling it down onto the bench's surface. A side spring slides cleanly and holds it in position. The dogs are 110mm(4.3/8") long, the pups 60mm(2.3/8"). Both work well in combination with Veritas Wonder Dog and Wonder Pup Clamps. For 19mm(3/4") dog hole.