Coarse spiral pattern with square drive end. Manufactured from carbon steel. Packed in plastic case on display card. Features and Benefits • Contents: one of each size: 1 (3-6mm), 2 (6-8mm), 3 (8-11mm), 4 (11-14mm) and 5 (14-18mm)Carbon steel Contents 1 x 3 - 6mm 1 x 6 - 8mm 1 x 8 - 11mm 1 x 11 - 14mm 1 x 14 - 18mm