Marshall Breaking Heads consist of an upper and lower cylindrical segment having an inside radius of curvature of 3" for a 6" sample. The lower segment is mounted on a base with two perpendicular guide rods extending vertically from the base. One guide rod is larger than the other, with a correspondingly larger guide sleeve in the upper segment to ensure correct assembly. Guide sleeves in the upper segment bring the two sections together without appreciable binding or loose motion on the guide rods. Meet ASTM D6927. H-1362 shipping wt. 30 lbs. (13.65kg)