Galvanized, carbon steel models

Fastener body units are stamped, using 11 gauge hot-rolled, pickled and oiled, steel coil, conforming to ASTM specification A-366.
Top units are stamped, using 16 gauge hot-rolled, pickled and oiled, steel coil, conforming to ASTM specification A-569.
Top and body units are mechanically galvanized, after stamping, with galvanizing conforming to ASTM specification B-695.
Threaded studs are grade 2 carbon steel, hex head cap screws, conforming to ASTM specification A-307, and mechanically galvanized. 

316 Stainless steel models
(Monel models identical but for substitution to all monel materials)

Fastener body units are stamped, using 13 gauge hot-rolled, annealed, stainless steel coil, conforming to ASTM specification A-240 and ASME specification SA-240.
Top units are stamped, using 16 gauge hot-rolled, annealed, stainless steel coil, conforming to ASTM specification A-240 and ASME specification SA-240.
Threaded studs are 316 stainless steel, hex head cap screws, conforming to ANSI specification B-18.2.1.
Internal tooth lock washers are 410 stainless steel, conforming to ANSI specification B-27.1. 

Aluminum models

Fastener body units are stamped, using 1/8" thick, grade 5052 aluminum plate, conforming to ASTM B-209 and Federal specification Q2A-250/8.
Top units are identical, except that 13 gauge plate is used.
Threaded studs are 6061 T-6 aluminum, hex head cap screws, conforming to Federal specification QQA-270.