HSSCO 코발트 테이퍼 생크 트위스트 드릴 비트, 6mm-40mm, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 1 개/19/20/21/22/23/24/25/26/27/28/30/40mm