NEMA locking-blade receptacles mount to surfaces and connect with plugs to distribute power. Also called NEMA locking-blade outlets, they secure when twisted to prevent unintended disconnections. These receptacles are made to standards designated by the US National Electrical Manufacturers Association (NEMA). They are rated for different current ratings and have various socket configurations to prevent mismatched connections. Industrial receptacles have rugged constructions suitable for harsh settings where impacts, corrosion, and hot/cold temperatures are concerns. Watertight receptacles seal out liquids and debris to provide connections in wet and corrosive environments.