Specification:
Item Type: Straight Flute Step Drill Set
Material: Plated High Speed Steel
Shank Type: Round Shank
4mm-12mm Step Drill Bit:
Blade Diameter: Approx. 4mm / 0.16in, 6mm / 0.24in, 8mm / 0.31in, 10mm / 0.40in, 12mm / 0.47in
Total Length: Approx. 65mm / 2.56in
Shank Diameter: Approx. 6mm / 0.24in
4mm-20mm Step Drill Bit:
Blade Diameter: Approx. 4mm / 0.16in, 6mm / 0.24in, 8mm / 0.31in, 10mm / 0.40in, 12mm / 0.47in, 14mm / 0.55in, 16mm / 0.63in, 18mm / 0.71in, 20mm / 0.80in
Total Length: Approx. 73mm / 2.87in
Shank Diameter: Approx. 8mm / 0.31in
4mm-32mm Step Drill Bit:
Blade Diameter: Approx. 4mm / 0.16in, 6mm / 0.24in, 8mm / 0.31in, 10mm / 0.40in, 12mm / 0.47in, 14mm / 0.55in, 16mm / 0.63in, 18mm / 0.71in, 20mm / 0.80in, 22mm / 0.87in, 24mm / 0.94in, 26mm / 1.02in, 28mm / 1.10in, 30mm / 1.18in, 32mm / 1.26in
Total Length: Approx. 101mm / 3.98in
Shank Diameter: Approx. 10mm / 0.40in
3mm Saw Drill:
Blade Diameter: Approx. 3mm / 0.12in
Total Length: Approx. 60mm / 2.36in
Shank Diameter: Approx. 3mm / 0.12in
6mm Saw Drill:
Blade Diameter: Approx.6mm / 0.24in
Total Length: Approx. 85mm / 3.35in
Shank Diameter: Approx. 6mm / 0.24in
8mm Saw Drill:
Blade Diameter: Approx. 8mm / 0.31in
Total Length: Approx. 93mm / 3.66in
Shank Diameter: Approx. 8mm / 0.31in
(Parameters are manually measured, there is a certain error)

Package List:
1 x 4-12mm Straight Flute Step Drill Bit
1 x 4-20mm Straight Flute Step Drill Bit
1 x 4-32mm Straight Flute Step Drill Bit
1 x 3mm Saw Bit
1 x 6mm Saw Bit
1 x 8mm Saw Bit
1 x Plastic Box

Note:
Can not be used for stainless steel, take safety when using.