All aluminum caps and plugs from Red Head Brass are made from rugged extruded 6061-T6
lightweight aluminum and hard-coated to MIL-A-8625 Type III, Class 1 to resist corrosion
and abrasion. All brass caps and plugs are made of Alloy C83600 ASTM B62, C84400
ASTM B584 or ASTM B505 (QQ-C-390).