With External Marking Points: Machined with external marking points, these ankle centers are used to precisely align stock for correct ankle or tenon placement. Steel: Anchor centers are made of steel, so you can use it for both hardwood and softwood. Full and Hollow Ankle Centers: There are solid and hollow ankle centers and you can choose which ones you need. Available in four sizes, 6mm ， 8mm ， 10mm ， 12mm: Available in four sizes, 6mm ， 8mm ， 10mm ， 12mm, the set contains two ankle centers of each size. Accurately mark the hole locations: just drill a set of holes, slide the centers of the dowel, and press the gasket together. The points on the centers of the studs will precisely mark the locations of the holes on the other member. Features: Machined with external marking points, these ankle centers are used to precisely align the stock for correct ankle or tenon placement.The ankle centers are made of steel, so you can use it as well for hardwood than for softwood.There are solid