Type P - Steel Zinc - 18-8 Stainless
Type S with Shoulder - Steel Zinc - 18-8 Stainless
Knurled - Plain Style - Aluminum - 18-8 Stainless
Knurled with Shoulder - Aluminum - 18-8 Stainless
Cold-Forged - Type-A, Steel Zinc
Stamped - Type-D, Steel Zinc