Abstract: A plug having a screw-down feature to securely connect to a socket of fixed, existing design. The plug includes flanges with screw receiving bores. Plug screws inserted through the bores deliver a coupling force for a variable compression seal that makes the connection waterproof. The screw-down connection includes upgrading the existing socket machine screws to a socket retaining member. The screw-down feature prevents the plug from accidentally disconnecting from the socket.

Abstract: A portable battery charging apparatus having two or more battery charging interfaces on separate panels. Wires electrically couple the battery charging apparatuses to a charger unit. The wires are routed for flexibility to fold and unfold the panels. The battery charging apparatuses and the charging unit may be connected to a flexible material. Each battery charging apparatus may include two or more charging jacks for the same or different batteries. The charger unit has an input to receive a power source, and an output to power a further device, for example a further battery charging apparatus.