This masthead fits on a DM-3 anodized, aluminum teardrop-shaped mast extrusion with standard 2 1/8 in. (54mm) by 2 3/4 in. (70mm) perpendicular measurement diameters. This masthead casting is complete with two Nylon sheaves and clevis pins. Use two SSP3 pop rivets to attach it to the mast section.