Dozer Moldboards have Four stypes.

Angle blade

Angle Dozers work best handling broken and granular materials, soils and gravel. The moldboard pivots about it’s center point to cast materials left or right. Ideal for making windrows, digging drainage ditches, backfilling trenches grading roads. This is a good all purpose blade, especially when equipped with Tilt Cylinders.

Straight blade

Straight Blades can be made very strong, abrasion resistant and puncture resistant for moving large, sharp and abrasive objects. They are not well suited to handling granular materials since these materials spill off the ends during long pushes. 
Straight Dozers are able to Tilt when equipped with one Tilt Cylinder and Tilt and Tip when equipped with two.

Semi-U blade

Built much like a Straight Blade but with a deeper profile and closed ends to help keep granular materials in front for long pushes. Semi-U Blades can be built with good abrasion resistance for materials like gravel, and with puncture resistance for handling large angular pieces of rock. 

Semi-U Blades are able to Tilt when equipped with one Tilt Cylinder and Tilt and Tip when equipped with two.

U blade

These blades are designed to push large quantities of granular materials over long distances. They are best suited for loose loads; coal, woodchips, and overburden, which are evenly distributed across the face of the moldboard. They are not well suited to handling large angular objects such as blast rock. 

U-Blades are able to Tilt when equipped with one Tilt Cylinder and Tilt and Tip when equipped with two.