Quick Change Tool Post Sets(USA Style), Piston Type Tool Post Sets (6 Pieces Sets) Made of Steel. Each set consists of one Piston type tool post and one of each of 5 tool holders: Style 1: Turning & Facing Style 2: Boring Turning & Facing Style 4: Boring, Heavy-duty Style 7: Universal Parting Blades Style 10: Knurling, Facing & Turning QCTP Thread Size: 0251-0200: 16x1.5mm Item Model Swing Description 0251-0100 AXA 6-12" Each 1pc: 0250-0100, 0250-0101, 0250-0102, 0250-0104, 0250-0107, 0250-0110 0251-0200 BXA 10-15" Each 1pc: 0250-0200, 0250-0201, 0250-0202, 0250-0204, 0250-0207, 0250-0210 0251-0300 CXA 13-18" Each 1pc: 0250-0300, 0250-0301, 0250-0302, 0250-0304, 0250-0307, 0250-0310 0251-0400 CA 14 "-20" Each 1pc: 0250-0400, 0250-0401, 0250-0402, 0250-0404, 0250-0407, 0250-0410