This Dowel Jig Kit is made to help you make accurate butt joints, miter joints and edge joints with ease Package included: 1Dowel Jig 2 x 1/4inch screws 2 x 5/16inch screws 2 x 3/8inch screws 2 x 3/8 inch inclined hole drill bits(9.5mm round and hexagol handle) 2Hex keys 2Stoppers Note: If the left and right distances of individual products are asymmetric and there is deviation during use, it can be adjusted by using following steps: Unscrew the left two screws with the hexagon socket. Adjust the large screw on the middle rod to make the distance between left and right of the product consistent. After the left and right distances are the same, tighten the left two socket head cap screws. Rotate the small rotating rod, and check whether the left and right distances are uniform in the experiment. After debugging, the left and right distances are the same.