Rhino-Rack Square Head Bolt is made of high quality durable and sturdy material which is offers good corrosion resistance in bad environment like high temperature, cold weather and high humidity areas. Controlled heat treatment produces maximum strength without brittleness. Precision forged for symmetrical grain flow maximum strength. Accurate control of socket depth gives more wrench engagement permits full tightening without cracking or reaming the socket. Head with increased bearing area for greater loading carrying capacity. Size: M6 x 25 mm. Comes in silver colour. Pack contains 4 pieces bolt.