The left-wound and right wound spiral are alternately arranged and jointed with the straight rods. If the rod pitch is less than two-fold spiral pitch, the belts are called A2. If the rod pitch is equal to or greater than two-fold spiral pitch, the belts are called F2.
Advantages
The surface is flat, so that unstable items can be carried.
The allowable tension is high, so that heavy load can be carried.
The belts can be used at high temperature.
The belts can have tight mesh, they can carry small materials.
