Turbo Variable Flow Actuator Bolt for 2007-2012 Acura RDX K23A1 with 2300DO-VT.T Engine. Made From Billet Hardened 4140 steel. M6x1.0 Left Hand Thread. 15.05mm Eye Hole. Hardness 37 Rockwell HRC (HARDEST ON THE MARKET). MADE IN USA. Each bolt is made from a 3-D model generated from our coordinate measuring machine (CMM) with machining tolerances of .05mm (.002in). Machined out of billet 4140 steel alloy. Heat treated to a hardness of Rockwell C37, guaranteed to never wear out.