The flyer inserts twist. Each flyer rotation creates one turn in the roving. In the final analysis therefore, since the flyer rotation speed is kept constant, twist per unit length of roving depends upon the delivery speed, and can be influenced accordingly. High levels of roving twist represent production losses and might lead to draft problems in the ring spinning machine. On the other hand, low twist levels can cause false drafts or even roving breaks during bobbin winding. Normal twist levels are shown in the following diagram (as provided by Rieter).