The Hettich Accura Drill Guide BlueJig is designed to be used with steel dowels to make holes in wood. The drill guide has dimensions of 20 mm, 24 mm, and 30 mm, and can be used with drilling dimensions of 24 mm and 34 mm. The drill guide also has a dimension of 25 mm, which is the size of the dowel clamping. The drill guide is designed to be used with existing Rastex holes, and has two pick-off pins to help with positioning. The drill guide is made of plastic with hardened drill bushes made of steel. For front holes for mounting steel dowels.  Rastex 15 with dowel clamping dimension: 20 mm, drilling dimension 24 mm. Rastex 15 with dowel clamping dimension: 30 mm, drilling dimension 34 mm Rastex 25 with dowel clamping size 24.5 mm, drilling dimension 33.5 mm. Practical positioning of the drill guide to existing Rastex holes through 2 pick-off pins, diameter 15 and 25 mm. With wedges for thickness: 15/16, 18/19 and 21/22mm. Designed for combination bore with wood wall plugs. Plastic with hardened drill bushes made of steel.