21-22 H6 (second generation) special ★ plastic steel (non-metallic) 21-22 H6 (second generation) special ★★ thickened manganese steel 3D full enveloping 21-22 H6 (second generation) special ★★★ thickened aluminum magnesium alloy 3D full enveloping 21-22 H6 (second generation) special ★★★★ high strength carbon steel 3D full enveloping 21-22 H6 (third generation) special ★★ thickened manganese steel 3D full enveloping 21-22 H6 (third generation) special special ★★★ thickened aluminum magnesium alloy 3D full enveloping 21-22 H6 (3nd generation) special ★★★★ high-strength carbon steel 3D full enveloping 21 H6S (1.5T) special ★★ thickened manganese steel 3D full enveloping 21 H6S (1.5T) special ★★★ thickened aluminum magnesium alloy 3D full enveloping 21 H6S (1.5T) special ★★★★ high strength carbon steel 3D full enveloping 21 H6S (2.0T) special ★★ thickened manganese steel 3D full enveloping 21 H6S (2.0T) special ★★★ thickened aluminum magnesium alloy 3D full enveloping 21 H6S (2.0T) special ★★★★ high strength carbon steel 3D full enveloping 13-20 H6 (1.5T 2.0T) special ★ plastic steel (non-metallic) 13-20 H6 (1.5T 2.0T) special ★★ thickened manganese steel 3D full enveloping 13-20 H6 (1.5T 2.0T) special ★★★ thickened aluminum magnesium alloy 3D full enveloping 13-20 H6 (1.5T 2.0T) special ★★★★ high strength carbon steel 3D full encirclement