Yokomo ZC-TB18T 18mm Titanium Turn Buckle (2pcs)  [ZC-TB18T]

　that is a particular screw manufactured with a reverse thread on a single part of screw at both ends, which allows one to adjust the spacing between your parts at both ends whenever rotated in one way. Mainly utilized for top arms and connect rods, making it easy to adjust camber and toe angle. There is a stamp on the reverse threaded part of center.
Normal kits usually utilize steel turnbuckles, but by changing to titanium, you can somewhat reduce the fat. In particular, the top of arm is mounted high, which plays a part in fat loss and a diminished center of gravity. It is part that will increase the quality of machine with high precision cutting and high accuracy. The distance is 18mm and there are 2 pieces.