Hardened tool steel tips. Phillips bits - S2 Industrial quality steel, heat treated and hardened for longer life. 10 piece Robertson/Phillips Carabiner clip. Set contains: (1) PH no 1, (2) PH no 2, (1) PH no 3, (1) Robertson no 0, (1) Robertson no 1, (3) Robertson no 2 and (1) Robertson no 3.