99e4ab93_Parlec___Rough___Finish_Boring_H_AND_FINISH_BORING_RANGE_TREE_Component_2
[0] 3 [Component] Twin Rough Boring Head [Catalog Page] Page 16 [Component_2] 
Select when metal removal is the goal and bore tolerance is larger. Setting on a presetter will provide accurate bore but adjustment for insert wear is not easily done at the machine.
Parlec : Rough & Finish Boring
Component_2