Sil 0625 P16 Internal Threading Holder For Size 16 Laydown Threading Inserts Sil 0625 P16 Internal Threading Holder: Neck Diameter = 5/8 Inch With A 3/4 Inch Round Shankd Diameter Left Hand Boring Bar Internal Lay Down Threading Holder For Size 16 Inserts Kd Diameter Left Hand Boring Bar Internal Lay Down Threading Holder For Size 16 Inserts Tmx Toolmex Part #6-Sil-625-P16