Is annealed and has electrolytic tin plating

491B accepts Master Lock® and American Lock® safety padlocks as well as most lockout hasps

Surface: Phosphated (anti-corrosion) (stated in the product description)

Extractable ions (ppb): Chloride 17

(unmated): IP2X

Adapter forniklet A-SLK4-N Grå MIL6225101401 Is annealed and has electrolytic. Adapter, made of brass can be screw mounted into 4 mm sockets. The expandable 4 mm plug of this adapter can be locked into the socket by tightening the grub screw. Assembled, the adapter offers complete touch proof protection. 4 mm rigid socket in insulator accepting spring loaded 4 mm plugs with rigid insulating sleeve.