The triangle

By allocating each 3 cutting edge on equilateral triangle positions on the same latitude, unparalleled smooth and stable reaming without center runout is possible and it makes reaming shape more accurate.

The durability

In general, more load occurs in cutting edges around the equatorial region during reaming.
By allocating more cutting edges in that region, such load is dissipated and the durability of cutting edges improves to the extent no other products ever realized.